CA2045547A1 - Process - Google Patents
ProcessInfo
- Publication number
- CA2045547A1 CA2045547A1 CA002045547A CA2045547A CA2045547A1 CA 2045547 A1 CA2045547 A1 CA 2045547A1 CA 002045547 A CA002045547 A CA 002045547A CA 2045547 A CA2045547 A CA 2045547A CA 2045547 A1 CA2045547 A1 CA 2045547A1
- Authority
- CA
- Canada
- Prior art keywords
- transesterification
- esters
- fatty alcohol
- alcohols
- ester
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C31/00—Saturated compounds having hydroxy or O-metal groups bound to acyclic carbon atoms
- C07C31/02—Monohydroxylic acyclic alcohols
- C07C31/125—Monohydroxylic acyclic alcohols containing five to twenty-two carbon atoms
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/132—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group
- C07C29/136—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH
- C07C29/147—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH of carboxylic acids or derivatives thereof
- C07C29/149—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH of carboxylic acids or derivatives thereof with hydrogen or hydrogen-containing gases
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/132—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group
- C07C29/136—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/03—Preparation of carboxylic acid esters by reacting an ester group with a hydroxy group
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
- C07C69/02—Esters of acyclic saturated monocarboxylic acids having the carboxyl group bound to an acyclic carbon atom or to hydrogen
- C07C69/22—Esters of acyclic saturated monocarboxylic acids having the carboxyl group bound to an acyclic carbon atom or to hydrogen having three or more carbon atoms in the acid moiety
- C07C69/24—Esters of acyclic saturated monocarboxylic acids having the carboxyl group bound to an acyclic carbon atom or to hydrogen having three or more carbon atoms in the acid moiety esterified with monohydroxylic compounds
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Iron Core Of Rotating Electric Machines (AREA)
- Glass Compositions (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Fats And Perfumes (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Saccharide Compounds (AREA)
- Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
Abstract
A process is described for separating fatty alcohols from a fatty alcohol fraction which contains a minor amount of a lower alkyl (e.g. methyl) fatty acid ester or esters. The fatty alcohol fraction is subjected to transesterification to convert substantially all of any lower alkyl ester present to wax ester or esters. The resulting lower alkanol (e.g. methanol) is evaporated. Then the intermediate transesterification mixture is distilled to recover fatty alcohols. The residue from this distillation step is mixed with excess lower alkanol and again transesterified to reconvert wax ester or esters to lower alkyl esters. This mixture is re-distilled and the recovered mixture of lower alkanol and fatty alcohol or alcohols can be recycled. If an alkyl titanate is used as transesterification catalyst then both distillation steps can be effected without prior separation of the catalyst and the non volatile residue from the second distillation step can be recycled to the first transesterification step.
Description
woso/oxl2~ PCT/GB90/~065 ` 20~47 . , .
PROCESS
This invention relates to a process for the production of alcohols. ~ore particularly it relates to a process for the production and refining of fatty alcohol products obtained by hydrogenation of esters.
Fatty alcohols, or higher alcohols as they are sometimes designated, are monohydric aliphatic alcohols containing si~ or more carbon atoms which are derived either from natural sources or are synthesised from petroleum feedstocks. They are often classified by their market usage. As the primary end use of primary alcohols containing between about 6 and about 11 carbon atoms is the production of plasticiser esters, such alcohols are often termed plasticiser alcohols. For higher alcohols containing, fo~ example, from about 11 up to about 20 carbon atoms, the major use is for the production of synthetic detergents; hence such alcohols are often termed detergent alcohols. The distinction between plasticiser alcohols and detergent alcohols is somewhat arbitrary and there is some production of phthalate esters from a C13 "oxo" alcohol and also some production of, for example, nonionic surfactants from C8 to C10 alcohols.
Although there are some natural products which -~
contain esters which can be hydrogenated to produce alcohols ~`
in the plasticiser range, these are more usually produced synthetically from petroleum feedstoc~s by, for example, the so-called "oxo" process, a p~ocess which is also termed oxonation or hydroformylation. Detergent range alcohols, on the other hand, are typically produced by hydrogenation of low molecular alkyl esters of fatty acids. Such esters can be produced by transesterification of natural triglycerides or by esterification of the fatty acids obtained by hydrolysis of such triglycerides. Examples of triglycerides which can be used as raw materials include natural oils, such as coconut oil, rape seed oil, and palm oils, and , . ,, ., ,., , . , . .. ~.
:, : ' . ,, . ................. ,. ',, '' ' , ,,, : !
, ,, ,' ''~ . ~ ' . - ' ' .:
WO90/08123 PCTIGB90/~065 5 4~
animal fats, such as lard, tallow, and fish oil. As such natural raw materials usually contain mixtures of triglycerides, the alcohol products obtained upon hydrogenation are also mixtures of n-alkanols of differing molecular weight. Such mixtures of alkanols are acceptable for production of detergents without prior separation of the alkanols one from another.
Whatever the commercial end use of the fatty alcohol or fatty alcohol mixture the user generally insists that the alcohol product must have as low an acid value as possible and also as low a saponification value as possible.
The acid value (AV) is a measure of the free acid content of the alcohol product and is defined as the number of mg of ROH required to neutralise the free fatty acid in l g of alcohol. The saponification value ~SV) gives, together with the acid value, a measure of the free ester content of the alcohol product and is defined as the number of mg of KOH
re~uired to saponify the esters and acids in l g of alcohol.
The ester value (EV) is the number obtained by subtracting the acid value from the saponification value (EV = SV -AV). In all cases the lower the value is (AV, SV, or EV), the better is considered to be the quality of the alcohol product. Another measure of purity of saturated alcohols is the iodine value ~IV), i.e. the number of g f I2 absorbed by l0~ g of the alcohol. The iodine value indicates the ethylenic double bond content of the alcohol product.
Again, it is generally considered desirable to have as low an iodine value as possible for a saturated alcohol.
Examples of commercial fatty alcohol products are the products sold under the following trade names:
- -- : :
, , ~ :
WO 90/08123 PCl'/GB90100065 _ 3 -2Q~5~ t z o o o o o :r 5 o rt 1 O ~ O
t ~ rr X X r~ ~r ~ o~
O~ C~ C~ ~ C~ ~ ~ ~ ~ D~ n Q ~ ~
O ~r o o o o o o o o o ~
Z
cr p, 3 o ~-3 C1 ~ ~3 5 a) O D' O O ~D O
a- G
, ~ ~a u- ~ ~ ~ ~ ~ 3 o 1- dP O
.
1-- 3 ~ C1 O Pl O O O O tl) -:
O
G C 0 1-- 0 0 0 0 1-~
O ~ 3 ~ 3 3 :~ C
O O ~
O . .
tn u~ 3 :~
X
,,~ ,p ~_ ,~, ~ o~ ~ Q : ~
o ' i' ' o N ~ ~ O
co c h~ ~- 3 .:
~t O
l_ ~ O
tO
.: - ' ' ' ' : '~ ; ':
` '' . :. .
., ' . '.' ' . : ' .
~". ' ' ' ` ~ ' ` .
., ' '.,, :,. .
Woso/n8l23 PCT/GB90/00065 - The esters usually used as raw materials for the produc'ion of detergent range alcohols are the methyl esters. A problem arises in refining of the product alcohol mixtures because the boiling point of one or more of the methyl esters present in the ester mixture which is hydrogenated will usually be close to that of one of the product alcohols. Hence it becomes difficult, if not impossible, to separate by distillation any unconverted methyl esters from the product alcohol mixture.
As an illustration of the difficulty of separating fatty alcohols from methyl fatty acid esters, particularly from mixtures containing a major amount of a mixture of fatty alcohols and a minor amount of a mixture of methyl fatty acid esters, reference may be made to the following list of boiling points:
I Substance Boilinq ~oint Pressure mm Ha (bar)i ¦l-dodecanol 150C 20 (0.027) methyl laurate 149C 20 (0.027) l-tetradecanol 167C 15 (0.020) methyl myristate 170C 15 (0.020) l-hexadecanol 189.5C 15 (0.020) methyl palmitate 192C 15 (0.020) l-octadecanol 210C 15 (0.020) methYl stearate 213C 15 (0.020) A mixture containing all of these components, such as might be produced by hydrogenation of a mixture of methyl esters of C12- to Clg-fatty acids produced by hydrolysis of a natural triglyceride, is difficult (if not impossible) to separate satisfactorily by distillation without recourse to use of multiple distillation columns. To avoid the expense of multiple distillation columns, one of two approaches is normally adopted. The first approach involves use of somewhat vigorous hydrogenation conditions, including use of high pressures and temperatures so as to ensure that as :
.; . . ., :
. . .
w~so/08123 PCT/GB90/00065 - s - 20~5547 small a proportion of unconverted methyl esters remains in the hydrogenation product. Although this largely obviates the problem of separating the methyl esters from the product alcohols, the use of vigorous hydrogenation conditions has drawbacks, particularly in that such conditions also tend to increase the yield of alkane and ether byproducts which represent a significant loss of potentially valuable alcohols. In addition catalyst consumption is rather high and the use of high pressure equipment increases the capital and running costs of the plant.
The second approach to the problems associated with the presence of unconverted esters in the alcohol hydrogenation product is to use less vigorous hydrogenation conditions, which reduces the loss of alcohol product by formation of alkane and ether byproducts, with subsequent removal of the unconverted ester by hydrolysis with hot aqueous alkali, such as hot sodium hydroxide solution. In this case the remaining ester is converted to a fatty acid salt which is lost in the aque~us phase. In addition this procedure involves consumption of sodium hydroxide or other alkali. Finally, as the sodium or other alkali metal salts of the fatty acids act as soaps, problems may arise in separating the aqueous phase from the alcohol product due to formation of emulsions.
For further background information about the production of fatty alcohols reference may be had to the following reviews:
1. "Fatty alcohols", by J.A. Monick, J. Rm. Oil Chemists' Soc., November 1979, Vol. 56, pages 853A to 860A;
PROCESS
This invention relates to a process for the production of alcohols. ~ore particularly it relates to a process for the production and refining of fatty alcohol products obtained by hydrogenation of esters.
Fatty alcohols, or higher alcohols as they are sometimes designated, are monohydric aliphatic alcohols containing si~ or more carbon atoms which are derived either from natural sources or are synthesised from petroleum feedstocks. They are often classified by their market usage. As the primary end use of primary alcohols containing between about 6 and about 11 carbon atoms is the production of plasticiser esters, such alcohols are often termed plasticiser alcohols. For higher alcohols containing, fo~ example, from about 11 up to about 20 carbon atoms, the major use is for the production of synthetic detergents; hence such alcohols are often termed detergent alcohols. The distinction between plasticiser alcohols and detergent alcohols is somewhat arbitrary and there is some production of phthalate esters from a C13 "oxo" alcohol and also some production of, for example, nonionic surfactants from C8 to C10 alcohols.
Although there are some natural products which -~
contain esters which can be hydrogenated to produce alcohols ~`
in the plasticiser range, these are more usually produced synthetically from petroleum feedstoc~s by, for example, the so-called "oxo" process, a p~ocess which is also termed oxonation or hydroformylation. Detergent range alcohols, on the other hand, are typically produced by hydrogenation of low molecular alkyl esters of fatty acids. Such esters can be produced by transesterification of natural triglycerides or by esterification of the fatty acids obtained by hydrolysis of such triglycerides. Examples of triglycerides which can be used as raw materials include natural oils, such as coconut oil, rape seed oil, and palm oils, and , . ,, ., ,., , . , . .. ~.
:, : ' . ,, . ................. ,. ',, '' ' , ,,, : !
, ,, ,' ''~ . ~ ' . - ' ' .:
WO90/08123 PCTIGB90/~065 5 4~
animal fats, such as lard, tallow, and fish oil. As such natural raw materials usually contain mixtures of triglycerides, the alcohol products obtained upon hydrogenation are also mixtures of n-alkanols of differing molecular weight. Such mixtures of alkanols are acceptable for production of detergents without prior separation of the alkanols one from another.
Whatever the commercial end use of the fatty alcohol or fatty alcohol mixture the user generally insists that the alcohol product must have as low an acid value as possible and also as low a saponification value as possible.
The acid value (AV) is a measure of the free acid content of the alcohol product and is defined as the number of mg of ROH required to neutralise the free fatty acid in l g of alcohol. The saponification value ~SV) gives, together with the acid value, a measure of the free ester content of the alcohol product and is defined as the number of mg of KOH
re~uired to saponify the esters and acids in l g of alcohol.
The ester value (EV) is the number obtained by subtracting the acid value from the saponification value (EV = SV -AV). In all cases the lower the value is (AV, SV, or EV), the better is considered to be the quality of the alcohol product. Another measure of purity of saturated alcohols is the iodine value ~IV), i.e. the number of g f I2 absorbed by l0~ g of the alcohol. The iodine value indicates the ethylenic double bond content of the alcohol product.
Again, it is generally considered desirable to have as low an iodine value as possible for a saturated alcohol.
Examples of commercial fatty alcohol products are the products sold under the following trade names:
- -- : :
, , ~ :
WO 90/08123 PCl'/GB90100065 _ 3 -2Q~5~ t z o o o o o :r 5 o rt 1 O ~ O
t ~ rr X X r~ ~r ~ o~
O~ C~ C~ ~ C~ ~ ~ ~ ~ D~ n Q ~ ~
O ~r o o o o o o o o o ~
Z
cr p, 3 o ~-3 C1 ~ ~3 5 a) O D' O O ~D O
a- G
, ~ ~a u- ~ ~ ~ ~ ~ 3 o 1- dP O
.
1-- 3 ~ C1 O Pl O O O O tl) -:
O
G C 0 1-- 0 0 0 0 1-~
O ~ 3 ~ 3 3 :~ C
O O ~
O . .
tn u~ 3 :~
X
,,~ ,p ~_ ,~, ~ o~ ~ Q : ~
o ' i' ' o N ~ ~ O
co c h~ ~- 3 .:
~t O
l_ ~ O
tO
.: - ' ' ' ' : '~ ; ':
` '' . :. .
., ' . '.' ' . : ' .
~". ' ' ' ` ~ ' ` .
., ' '.,, :,. .
Woso/n8l23 PCT/GB90/00065 - The esters usually used as raw materials for the produc'ion of detergent range alcohols are the methyl esters. A problem arises in refining of the product alcohol mixtures because the boiling point of one or more of the methyl esters present in the ester mixture which is hydrogenated will usually be close to that of one of the product alcohols. Hence it becomes difficult, if not impossible, to separate by distillation any unconverted methyl esters from the product alcohol mixture.
As an illustration of the difficulty of separating fatty alcohols from methyl fatty acid esters, particularly from mixtures containing a major amount of a mixture of fatty alcohols and a minor amount of a mixture of methyl fatty acid esters, reference may be made to the following list of boiling points:
I Substance Boilinq ~oint Pressure mm Ha (bar)i ¦l-dodecanol 150C 20 (0.027) methyl laurate 149C 20 (0.027) l-tetradecanol 167C 15 (0.020) methyl myristate 170C 15 (0.020) l-hexadecanol 189.5C 15 (0.020) methyl palmitate 192C 15 (0.020) l-octadecanol 210C 15 (0.020) methYl stearate 213C 15 (0.020) A mixture containing all of these components, such as might be produced by hydrogenation of a mixture of methyl esters of C12- to Clg-fatty acids produced by hydrolysis of a natural triglyceride, is difficult (if not impossible) to separate satisfactorily by distillation without recourse to use of multiple distillation columns. To avoid the expense of multiple distillation columns, one of two approaches is normally adopted. The first approach involves use of somewhat vigorous hydrogenation conditions, including use of high pressures and temperatures so as to ensure that as :
.; . . ., :
. . .
w~so/08123 PCT/GB90/00065 - s - 20~5547 small a proportion of unconverted methyl esters remains in the hydrogenation product. Although this largely obviates the problem of separating the methyl esters from the product alcohols, the use of vigorous hydrogenation conditions has drawbacks, particularly in that such conditions also tend to increase the yield of alkane and ether byproducts which represent a significant loss of potentially valuable alcohols. In addition catalyst consumption is rather high and the use of high pressure equipment increases the capital and running costs of the plant.
The second approach to the problems associated with the presence of unconverted esters in the alcohol hydrogenation product is to use less vigorous hydrogenation conditions, which reduces the loss of alcohol product by formation of alkane and ether byproducts, with subsequent removal of the unconverted ester by hydrolysis with hot aqueous alkali, such as hot sodium hydroxide solution. In this case the remaining ester is converted to a fatty acid salt which is lost in the aque~us phase. In addition this procedure involves consumption of sodium hydroxide or other alkali. Finally, as the sodium or other alkali metal salts of the fatty acids act as soaps, problems may arise in separating the aqueous phase from the alcohol product due to formation of emulsions.
For further background information about the production of fatty alcohols reference may be had to the following reviews:
1. "Fatty alcohols", by J.A. Monick, J. Rm. Oil Chemists' Soc., November 1979, Vol. 56, pages 853A to 860A;
2. ~Natural fats and oils route to fatty alcohols", by Henning Buchold, Chemical Engineering, ~ebruary 21, 1985, pages 42 and 43;
3. "Manufacture of Fatty Alcohols Based on Natural Fats and Oils", by Udo R. Xreutzer, JAOCS, Vol. 61, No. 2 (February 1984), pages 343 to 348;
, - .
WOgO~ORl~3 PCT/GB90tOo065_ ~ 4'1 4. "Production of Fatty Alcohols from Fatty Acids", by Theodor Voeste and Henning Buchold, JAOCS, Vol. 61, No. 2 tFebruary 1984), pages 350 to 352;
, - .
WOgO~ORl~3 PCT/GB90tOo065_ ~ 4'1 4. "Production of Fatty Alcohols from Fatty Acids", by Theodor Voeste and Henning Buchold, JAOCS, Vol. 61, No. 2 tFebruary 1984), pages 350 to 352;
5. "Alcohols, higher aliphatic", Kirk-Othmer Encyclopedia of Chemical Technology, Third Edition (1978), Vol. 1, (published by J. Wiley & Sons. Inc., New York), pages 716 to 739; and 6. nTechnical Processes for the Manufacture of ~atty Alcohols" by H.-D. Kompp and H.P. Rubersky, in "Fatty Alcohols - Raw Materials, Methods, Uses" published in 1982 by Henkel XGaA, Dusseldorf, at pages 49 to 74.
It would be desirable to provide a method enabling fatty alcohol products obtained by hydrogenation of esters to be purified by distillation, even though such products contain appreciable proportions of unconverted esters. The existence of such a method would enable hydrogenation of the ester feedstock to be carried out under relatively mild conditions with less formation of byproduct alkane and hence with higher yields of alcohol products than can be obtained by conventional methods of manufacture of fatty alcohols by this route.
The present invention accordingly seeks to provide an improved process for refining alcohols produced by hydroqenation of esters, such as methyl esters produced by transesterification of natural glycerides or by :.
esterification of fatty acids produced by hydrolysis of such triglycerides, wherein the crude hydrogenation product still contains a minor amount of unconverted ester starting material. It further seeks to provide an improved process for production of fatty alcohols from fatty alcohol fractions obtained by hydrogenation of low molecular alkyl -esters, especially methyl esters, of fatty acids derived from natural triglycerides, under conditions which minimise fonmation of byproduct alkanes and ethers followed by refining of the resulting ester containing hydrogenation .. .. .. .
~ . ~
wo ~/08123 PCT/GB90/~065 _ 7 _ ` 20~5~7 product.
According to the present invention there is provided a process for the recovery of a fatty alcohol or alcohols from a fatty alcohol fraction containing a major molar amount of at least one fatty alcohol and a minor molar amount of at least one lower alkyl fatty acid ester, which process comprises:
(a) subjecting the fatty alcohol fraction to transesterifica~ion in the presence of a transesterification catalyst in a first transesterification zone maintained under transesterification conditions, thereby to convert substantially all of any lower alkyl fatty acid ester present in the feed mixture by ester intexchange with a corresponding amount of fatty alcohol or alcohols to lower alkanol and to a wax ester derived from a fatty alcohol and a fatty acid;
~b) separating resulting lower alkanol-from the reaction mixture of step ta1 by vaporisation to yield an intermediate transesterification product mixture that is at least partially free from lower alkanol and contains a fatty alcohol or alcohols and a wax ester or esters:
(c) distilling fatty alcohol or fatty alcohols and wax ester or wax esters of the intermediate transesterification product mixture of step (b) to yield (i) an overhead fraction that contains the fatty alcohol or alcohols and is substantially free from lower alkyl fatty acid ester, and ~ii) a distillation residue comprising fatty alcohol or alcohols, and wax ester or esters;
(d) subjecting the distillation residue of step (c) to transesterification in the presence of added lower alkanol and of a transesterification catalyst in a second transesterification zone maintained under transesterification conditions, thereby to reconvert wax ester or esters to lower alkyl fatty acid ester or esters and to fatty alcohol or alcohols;
' ' -:.
WO90/08123 PCT/GB90/0006~
S~4~ - 8 -te) evaporating unreacted lower alkanol from the reacti-n mixture of step (d) to yield a liquid residue that is substantially free from lower alkanol; and ~f) distilling fatty alcohol or alcohols and lower alkyl fatty acid ester or esters of the liquid residue of step te) to produce (i) an overhead product containing a mixture of a lower alkyl fatty acid ester or esters and fatty alcohol or alcohols and (ii) a relatively involatile residue.
In another aspect the invention provides a process for the production of fatty alcohols which comprises hydrogenating a lower alkyl fatty acid ester or esters in a hydrogenation zone containing a charge of a hydrogenation catalyst and maintained under hydrogenation conditions to yield a mixture of (i) lower alkanol And (ii) a fatty alcohol fraction containing a fatty alcohol or alcohols and a minor amount of unreacted lower alkyl fatty acid ester or esters; and which further comprises:
(a) subjecting the fatty alcohol fraction to transesterification in the presence of a transesterification catalyst in a first transesterification zone maintained under transesterification conditions, thereby to convert substantially all of any lower alkyl fatty acid ester present in the feed mixture by ester interchange with a corresponding amount of fatty alcohol or alcohols to lower alkanol and to a wax ester derived from a fatty alcohol and a fatty acid;
tb) separating resulting lower alkanol from the reaction mixture of step (a) by vaporisation to yield an intermediate transesterification product mixture that is at least partially free from lower alkanol and contains a fatty alcohol or alcohols and a wax ester or esters;
(c) distilling fatty alcohol or fatty alcohols and wax ester or wax esters of the intermediate transesterification product mixture of step (b) to yield ti) an overhead ,. . .
.
WO90/0812~ PCT/GB90/00065 9 ~ 5 ~ 7 fraction that contains the fatty alcohol or alcohols and is substantially free from lower alXyl fatty acid ester, and (ii) a distillation residue comprising fatty alcohol or alcohols, and wax ester or esters;
(d) subjecting the distillation residue of step (c) to transesterification in the presence of added lower alkanol and of a transesterification catalyst in a second transesterification zone maintained under transesterification conditions, thereby to reconvert wax ester or esters to lower alkyl fatty acid ester or esters and to fatty alcohol or alcohols:
(e) evaporating unreacted lower alkanol from the reaction mixture of step (d) to yield a liquid residue that is substantially free from lower alkanol;
(f) distilling fatty alcohol or alcohols and lower alkyl fatty acid ester or esters of the liquid residue of step (e) to produce (i) an overhead product containing a mixture of a lower alkyl fatty acid ester or esters and fatty alcohol or alcohols and (ii) a relatively involatile residue; and (g) recycling material of the overhead product of step (f) to thP hydrogenation step.
In this specification the term "fatty alcohol"
means an alkanol, preferably a linear alkanol, containing from about 6 to about 26 carbon atoms. Preferred fatty alcohols contain from about lO to about 20 carbon atoms.
Typical fatty alcohols include l-decanol, l-dodecanol, l-tetradecanol, l-hexadecanol, l-octadecanol, l-octadecenol and the like, and mixtures thereof. The term "lower alkyl"
means Cl- to C4-alkyl, including methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl and sec-butyl. The preferred lower alkyl radical is methyl. Similarly the term "lower alkanol" embraces Cl to C4 alkanols, including m~thanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, and sec-butanol. Methanol is the preferred lower alkanol.
. . .. .
, .
. . .
WO90/~8123 PCT/GB90/00065 ` 20~5547 - lO -By the term "~atty acids" we mean alkyl or alkenyl carboxylic acids, preferably linear alkyl or alkenyl carboxylic acids, containing from about Ç to about 26 carbon atoms, preferably about 10 to about 20 carbon atoms.
Examples of such fatty acids are decanoic acid (capric acid), dodecanoic acid tlauric acid), tetradecanoic acid (myristic acid), pentadecanoic acid, hexadecanoic acid (palmitic acid), heptadecanoic acid (margaric acid), octadecanoic acid (stearic acid or isostearic acid), oct~decenoic acids (oleic acid, linoleic acid or linolenic acid), eicosanoic acid (arachidic acid) and docosanoic acid (behenic acid). Mixtures of fatty acids are of especial importance as raw materials from which the lower alkyl ~atty acid esters used as starting material in the hydrogenation step are prepared. Such mixtures of acids can be obtained by hydrolysis of naturaily occurring triglycerides such as coconut oil, rape seed oil~ palm oils, tallowt lard and fish oil. If desired, such mixtures of acids can be subjected to distillation to remove lower boiling acids having a lower boiling point than a chosen temperature and thus produce a "topped" mixture of acids,-to remove higher boiling acids having a boiling point higher than a second chosen temperature and thus produce a ltailed" mixture of acids, or to remove both lower and higher boiling acids and thus produce a l! topped and tailed" mixture of acids.
In the hydrogenation of lower alkyl fatty acid esters there can be used vapour phase hydrogenation conditions in which the composition of the gas stream is selected so that at all times the material in contact with the hydrogenation catalyst is above the dew point, preferably at least about 5C above the dew point. Suitable hydrogenation catalysts include known ester hydrogenation catalysts such as reduced copper oxide-zinc oxide (see GB-B-2116552), and copper chromite, and promoted copper chromite catalysts. The preferred catalysts are reduced wo9o~n812~ PCT/CB90/00065 11- 20~ 7 copper oxide-zinc oxide catalysts of the type disclosed in GB-B-2116552. The preferred copper chromite catalysts are those containing from about 25 to about 45 percent by weight of copper and from about 20 to about 35 percent by weight of chromium, calculated as metal. Typical hydrogenation conditions include use of temperatures of up to about 260C, such as temperatures in the range of from about 140C to about 240C, and pressures in the range of from about 5 bar to about 100 bar. Liquid phase hydrogenation conditions can alternatively be used, if desired, for production of a fatty alcohol fraction by hydrogenation of a lower alkyl fatty acid ester or esters. In liquid phase hydrogenation typical operating conditions include use of a temperature of from about 180C to about 300C and a pressure of from about 50 bar to about 300 bar.
The hydrogenation mixture obtained by hydrogenating a lower alkyl fatty acid ester or mixture of esters contains, in addition to a fatty alcohol or fatty alcohol mixture, also lower alkanol, such as methanol. The methanol or other lower alkanol is separated in any known manner, as by distillation in one or more stages, from the fatty alcohol or alcohols to yield a fatty alcohol fraction suitable for use in the process of the invention. Such a fatty alcohol fraction typically contains, besides possibly a minor molar amount of methanol or other lower alkanol (usually less than about 5 mole %), a major molar amount of a fatty alcohol or alcohols (usually about 90 mole % or more) and a minor molar amount of unreacted lower alkyl fatty acid ester or esters (usually less than about 5 mole % ) .
In transesterification step (a~ the fatty alcohol fraction is subjected to transesterification in the presence of a transesterification catalyst. Any known transesterification catalyst may be used. Examples include alkyl titanates, alkali metal alkoxides, and metallic tin : ~ .
, Wo ~/0812~ PCT/GB90/~065 20~ 7 - 12 -and stannous hydroxide. Although acids, such as sulphuric acid and sulphonic acids, have been proposed as liquid phase transesterification catalysts in the prior art, the use of such catalysts is best avoided since there is a risk of the fatty alcohol product becoming contaminated with sulphurous impurities. Other transesterification catalyst systems which have been proposed, but are not preferred, include bases, compounds of alkali and alkaline earth metals, water, and metals such as zinc, cadmium, lead and their compounds.
It is also contemplated that acidic resins containing, for example, -SO3H and/or -COOH groups or basic resins containing, for example, basic substituted ammonium groups can be used as transesterification catalysts.
A particularly preferred class of transesterification catalyst is the alkyl titanates. Any alkyl titanate may be added as catalyst but, as the alkyl titanate will itself participate in ester interchange, the alkoxide radicals originally present in the alkyl titanate will tend to undergo exchange with alkoxide radicals derived from the fatty alcohol or alcohols during the operation of the process of the invention.
Another particularly preferred class of transesterification catalyst is the alkali metal alkoxides, such as sodium methoxide or sodium ethoxide. Again exchange of alkoxide radicals in the catalyst with alkoxide radicals derived from the fatty alcohol or alcohols will tend to occur with time in the first transesterification zone.
Alternatively there may be used an alkali metal alkoxide derived from the fatty alcohol product itself, or from one or more of them if a mixture of fatty alcohols is to be prodllceq .
The transesterification conditions used in step (a) will to a large extent depend upon the activity of the transesterification catalyst. Although the use of elevated pressures is not ruled out, it will normally be preferred to .:
...-: .. -; :, : ....
:, .
WosO/081~3 PCT/GB90/~065 '~0~5~7 operate at a substantially atmospheric pressure or below, for example a pressure in the range of from about 0.1 bar to about 1.2 bar. In this way the vaporisation of methanol or other lower alkanol of step (b) is facilitated during the course of the transesterification reaction of step (a).
Removal of the lower alkanol during transesterification drives the transesterification reaction towards completion.
When ~sing an alkyl titanate a temperature of up to about 240C, such as a temperature in the range of from about 120C to about 200C, is typically used, for example a temperature of from about 170C to about 1~0C. Alkali metal alkoxides enable use of lower operating temperatures, e.g. in the range of from about 40C to about 100C, but normally require introduction of extra processing steps as will be further explained below.
Similar transesterification catalysts and temperature conditions can be used in step (d). However, it will usually be preferred to employ in step (d) a superatmospheric pressure, for example a pressure of from about 1.~ bar to about 50 bar, in order to maintain the lower alkanol (e.g. methanol) in the liquid phase in the second transesterification zone.
As already mentioned steps (a) and (b) are preferably conducted simultaneously in a first transesterification zone that has provision for recovery overhead of the liberated lower alXanol.
An advantage of the use of an alkyl titanate as transesterification catalyst is that the subsequent distillation and/or evaporation steps ~i.e. step (c) and steps (e) and (f)) can be conducted without prior removal of the catalyst. However, when using an alkali metal alkoxide as transesterification catalyst, it is preferable to neutralise the catalyst prior to distillation and/or evaporation. Conveniently this neutralisation step can be effected by passing the catalyst containing material through .
WO90/08123 PCT/GB90/0~65~
20~554~ - 14 -a bed of an ion exchange resin containing -SO3H and/or -COOH
groups, thus removing the alkali metal from the liquid mixture:
R- SO3 H + NaOR' = RSO3Na + HOR ', where R represents the resin and -OR ' represents an alkoxide radical.
A further advantage of the use of alkyl titanates is that the catalyst remaining in the relatively involatile residue of step (f) can be used to form at least a part of the transesterification catalyst used in step ~a). The balance of any amount of catalyst required can then be supplied by make up alkyl titanate. Control of "heavies" in the process can be achieved by purging a part of the relatively involatile residue of step ~f); the remainder of this relatively involatile residue can be recycled for use in step (a).
When using an alkali metal hydroxide as transesterification catalyst, on the other hand, there will usually be no residual catalyst in the relatively involatile residue of step (f) as neutralisation will usually be practised prior to any distillation step. Similarly, if a resin catalyst is used as a transesterification catalyst, there will be no catalyst dissolved in the relatively involatile residue of step (f). Hence recycle of the relatively involatile residue has no benefit in these cases and the relatively involatile residue of step (f) can be purged from the plant and used as fuel.
If an alkyl titanate transesterification catalyst is used, steps (e) and (f) can be carried out without prior removal of the catalyst. In this case it is best to operate with as short residence times as possible in these steps so as to minimise the risk of substantial reversion of the transesterification reaction with consequent re-formation of wax esters in these steps. Hence it is preferred to effect step ~e) by flash distillation so as to minimise the ..~ . ~ , ~ , .
.
w~o/n812~ PCT/GB90/00065 - 15 - 2~55(~'7 residence time in this step and to ef~ect step (f), for similar reasons, in a falling film or wiped film evaporator.
Distillation steps (c) and (f) are normally effected at or near atmospheric pressure or below, for example at a pressure in the range of from about 0.005 bar to about 1.2 bar.
In order that the invention may be clearly understood and readily carried into effect two preferred forms of alcohol production plant designed to operate according to the teachings of the present invention will now be described, by way of example only, with reference to the accompanying drawings, Figures 1 and 2 of which are each a flow diagram of a respective plant.
It will be understood by those skilled in the art that the drawings are diagrammatic and that further items of equipment such as reflux drums, pumps, vacuum pumps, temperature sensors, pressure sensors, pressure relief valves, control valves, flow controllers, level controllers, holding tanks, storage tanks, and the like may additionally be required in a commercial plant. The provision of such ancillary items of equipment forms no part of the present invention and is in accordance with conventional chemical engineering practice.
Referring to Figure 1, a hydrogenation plant 1 is supplied in line 2 with a feed ester stream, in line 3 with recycled material, and in line 4 with a hydrogen stream.
The feed ester stream in line 1 is a mixture of methyl esters obtained by esterification of a fatty acid mixture obtained by hydrolysis of coconut oil, followed by "topping and tailing~. This fatty acid mixture contains approximately 65 mole % dodecanoic acid, 25 mole %
tetradecanoic acid and 10 mole % hexadecanoic acid.
~ ydrogenation plant 1 can operate using any suitable ester hydrogenation process and with any suitable ester hydrogenation catalyst. A reduced copper oxide-zinc " , . . . ~, . . .
..
~: ' :: ~ , ; -~, ~
woso/oxli~ PCT/GB90/0006~
2~5~ - 16 -oxide catalyst of the type disclosed in GB-B-2116552 is an example of a suitable hydrogenation catalyst. Plant 1 may include one or more hydrogenation stages, as well as a preliminary distillation zone for separating at least a major part of the by-product methanol. The hydrogen stream in line 2 is produced in conventional manner from synthesis gas followed by a water gas shift reaction, CO2 removal and, if desired, further purification by pressure swing absorption. It may contain one or more inert gases, such as nitrogen, methane and argon. The byproduct methanol can be recycled for production of further methyl esters in line 5. A purge gas stream is taken from hydrogenation plant 1 in line 6. Hydrogenation plant 1 can operate using a vapour phase regime in which the reaction mixture in contact with the catalyst is always above its dew point. Alternatively it may be operated using a liquid phase regime, in which case a copper chromite catalyst will usually be preferred.
A crude fatty alcohol stream is recovered from plant 1 in line 7. This contains a minor amount of unconverted methyl esters, besides minor amounts of by-product alkanes, unknowns and "heavies". The crude fatty alcohol stream passes through heat exchanger 8 in which its temperature is adjusted to about 160C to about 200C, preferably about 170C to about 190C, e.g. 190C. The hot stream in line 9 is admixed with a mixture of fresh and recycled ester interchange catalyst ~transesterification catalyst), e.g. an alkyl titanate, supplied in line 10 and passes into a first ester interchange reactor 11 which provides a first transesterification zone. Reactor 11 is designed so as to provide a residence time therein in the range of f rom about 10 minutes up to about 120 minutes, preferably from about 15 minutes to about 60 minutes. ~he length of the residence time depends upon the temperature of the stream in line 9 and in react~r 11, as well as the effectiYe concentration of the alkyl titanate supplied in .
"` . : ~ .
, WOso/08123 PCT~GB90~065 2 0 ~ 7 line lO. In reactor ll the methyl esters of the fatty acids present in the feed stream in line 7 are converted to wax esters, i.e. fatty alcohol esters of the acid moieties of the methyl esters, by transesterification of the methyl esters with product fatty alcohols. Most of the methanol formed by transesterification is recovered as a vapour in line 12 from the vapour space in vessel ll and can be condensed and recycled to the methyl ester production plant (not shown).
The product from the first ester interchange reactor ll contains, besides a major molar amount of product alcohols, also minor molar amounts of alkane by-products, wax esters and "heavies", as well as traces of methanol. It is passed via line 13 into a product column 14 which is provided with three beds of structured packing 15, 16 and 17. Light ends, consisting mainly of alkane by-products, as well as traces of methanol, are recovered overhead in line 18 and are condensed by means of condenser l9. The resulting condensate in line 20 accumulates in reflux drum 21 which is vented to a vacuum pump (not shown) operating at 0.005 bar by line 22. Some alkanes are returned to product column 13 via line 23, pump 24 and line 25 to provide a reflux stream, whilst the net production of alkanes passes via line 26 to storage.
Product alcohols are withdrawn as vapour from product column 14 in line 27 and are condensed by means of condenser 28. The condensate passes on in line 29 to product drum 30 which is vented to a vacuum unit ~not shown) by line 31. Liquid product alcohols are passed via line 32, pump 33 and line 34 to product storage.
Bottoms product is withdrawn from product column 14 in line 35 and passed via line 36 to a falling film reboiler 37 which is operated at a temperature in the range of from about 210C to about 245~C, e.g. 240C. Part of the bottoms product is withdrawn in line 38 and is pumped by .. . .. ... . ., ~, . . . ., : ~
' - , . ~ ,' I ~- ~ ,, :. . ~ , 204~ 18 -pump 39 via line 40 to heat exchanger 41. Prior to entry to heat exchanger 41 excess methanol from line 42 is admixed with this part of the bottoms product. The quantity of methanol admixed via line 42 is typically at least about 5 times the stoichiometric quantity equivalent to the wax esters present in the bottom product up to about 100 times this stoichiometric quantity, for example about 80 times the stoichiometric quantity. In this way the equilibrium between wax esters and methanol, on the one hand, and methyl fatty acid esters, fatty alcohol and excess methanol, o~ the other hand, is shifted away from wax ester formation towards methyl fatty acid ester formation.
In heat exchanger 41 the temperature of the mixture of methanol and bottoms product, which still contains alkyl titanate transesteri~ication catalyst, is adjusted. The mixture passes on via line 43 to a second ester interchange reactor 44 which provides a second transesterification zone and is designed to provide a residence time of from about 30 minutes to about 240 minutes, preferably from about 60 minutes to about 180 minutes, e.g. about 120 minutes. The temperature in reactor 44 lies in the range of from about 160C to about 195C e.g.
about 180C. The size, and hence the residence time, selected for reactor 44 should be sufficient to allow the ester interchange to proceed to equilibrium at the temper~ture selected. The pressure in reactor 44 is typically about 42 bar. From second ester interchange reactor 44 the resulting transesterification product mixture is fed via line 45 through a pressure let down valve 46 to reduce its pressure to about 1.3 bar. It then continues in line 47 to a heated flash vessel 48. Methanol vapour is recovered overhead in line 49 and is condensed by means of a condenser ~not shown) for reuse elsewhere in the plant or for manufacture of further methyl esters.
The residual liquid phase exits flash column 48 in WO90/08l23 PCT/GB90/00065 2 ~ 7 line 50 and is pumped by pump 51 through line 52 via a pressure let down valve (not shown) to falling film evaporator 53 which is operated at a maximum temperature of about 240C and at a pressure of about 0.005 bar. A mixture of vapour and liquid exits falling film evaporator 53 in line 54 and passes into separation drum 55. The vapour is recovered in line 56 and condensed by condenser 57. The resulting condensate is passed in line 5~ to drum 59 which is connected to a vacuum system (not shown) by line 60. The liquid condensate, which comprises a mixture of product fatty alcohols, methyl esters, some methanol and traces of by-products, is recovered in line 61 and pumped by pump 62 .
to form the recycle stream in line 3.
The liquid from drum 55 is passed by line 63 and pump 64 either for waste disposal via line 65 or for recycle via line 66 to line 10.
Fresh alkyl titanate transesterification catalyst can be added as required via line 67.
The approximate flow rates of various of the streams expressed in molar units are summarised in Table 1 below:
.. ~ , , WO 90/08123 PCI`/GB90/00065 _ 20 -~o~547~ 3 ~ c ~ 3 t~
r 3 1~ tl) ~-~ x ;~ ~ ~ ~ :1 t~ 5 Pl 3 D) tt r~ 5 ~ O ~D 3 ~ <
a ~- u~ ~D ~
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WO~0/08l2~ PCT/GB90/~065 - 21 - 204~5~7 Figure 2 illustrates a modified form of the plant of Figure l which is designed to operate using an alkali metal alkoxide as the transesterification catalyst in place of an alkyl titanate. In Figure 2 like reference numerals have been used to indicate similar parts to those illustrated in Figure l.
The temperature of the crude fatty alcohol stream in line 7 is adjusted to 45C in heat exchanger 8. A
solution containing 10% w/v of sodium methoxide in dry methanol is added in line lOl so as to provide a concentration of 0.05% w/v of sodium methoxide in the material flowing in line 102. In this plant first ester interchange reactor 11 is designed to provide, typically, a residence time therein of about 30 minutes. The material exiting reactor ll in line 13 is then passed through a bed 103 of ion exchange resin in vessel 104 to neutralise the catalyst. The ion exchange resin of bed 103 can contain sulphonic acid and/or carboxylic acid groups. The catalyst free stream passes on in line 105 to product column 14.
Removal of the sodium methoxide catalyst prior to distillation in product column 14 is desirable so as to obviate the formation of condensation by-products and dark coloured organic tars, which would be promoted by the presence of sodium methoxide in the mixture at the elevated temperatures prevailing in the product column 14.
Recovery of product alcohol in product column 14 -is effected in the same way as for the plant of Figure 1.
The bottom product in lines 35, 38 and 40 is then cooled to about 50C in heat exchanger 41. A similar stoichiometric exc~ss of methanol is added from line 106 to the liquid stream in line 43. The resulting mixture in line 107 is -then admixed with a 10~ w/v solution of sodium methoxide in dry methanol supplied by way of line 108 at a rate sufficient to provide a concentration of about 0.05% w/v ~-sodium methoxide in the mixed stream in line 109 before ... ~ . . . .
.
- : , , ' ~
: - . , '' ' ' PCrtGB90/00065 w~/081~
~o~5~7 - 22 -entry to sec~nd ester interchange reactor 44 which is designed for a residence time of about 120 minutes. The interchanged product stream in line 45 is then passed through a second bed 110 of ion exchange resin, which contains, for example, sulphonic acid groups and/or carboxylic acid yroups, in vessel lll. This removes sodium ions from the liquid phase and neutralises the sodium methoxide transesterification catalyst. The neutralised liquid phase passes on in line 112 to flash column 48.
As the material in line 112 contains no transesterification catalyst there is no need to recycle "heavies" via line 66 (as in the plant of Figure 1).
Moreover, as there is no catalyst remaining in the material in line 112, the risk of reversion of methyl esters to wax esters and loss of methanol vapour in columns 48 and 53 by ester interchange with fatty alcohols product is obviated.
In a modification of the plant of Figure 2 columns 48 and 53 are replaced by a batch still (not shown). In this case the material in line 112 is collected until there is sufficient to justify operating the batch still.
The invention is further illustrated in the following Examples.
Example l A crude fatty alcohol product containing a minor amount of unconverted fatty acid methyl esters was prepared by hydrogenating in a laboratory hydrogenation reactor under vapour phase conditions (i.e. under conditions such that the reaction mixture in contact with the catalyst was at all times above its dew point) a mixture of fatty acid methyl esters obtained from a "topped and tailed" fatty acid mixture produced by hydrolysis of coconut oil. The catalyst used was a reduced copper oxide-zinc oxide ester hydrogenation catalyst. Prior to use the crude alcohol product mixture was distilled to remove substantially all the methanol produced as coproduct in the hydrogenation - - , , .
.
. .
Wo ~/0812~ PCT/GB90/00065 - 23 - 20~
step.
Three samples of the substantially methanol free crude fatty alcohol product were each heated to 200C under a nitrogen atmosphere for 30 minutes at 0.99 bar with 0.03%
w/w of Tilcom BIP (trade mark of Tioxide Chemical Division of British Titan Products p.l.c.). This material is reported to be a mixed lso-propyl/n-butyl titanate.
Subsequent analysis showed that, in the presence of a large excess of fatty alcohols and under conditions allowing methanol to escape from the reaction system, substantially all of the methyl esters had been transformed into wax esters. The results are plotted in Table 2 below which indicates the amounts of the components present in % w/w.
In Table 2 "C12 Me ester" means methyl dodecanoate, whilst "C14 Me ester", "C16 Me ester", and "C18 Me ester" represent respectively the corresponding methyl esters of the C14, C16 and C18 carboxylic acids. There were detected sixteen unidentified compounds, listed as "Unknowns 1 to 16" in Table 2, in minor or trace amounts. -~
. ~ , ... . .. . . . . . .
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WOs~/08123 PCT/GB90/~065 5 ~ 4~7 Table 2 _.. .. . .. _ _ COMPONENT FEED I R~n 1 , Run 2 Run 3 Methanol 2.19 l 0.03 ~ 0.11 1 0.02 C12 Alkane 0.34 ¦ 0.27 1 0.20 j 0.24 C14 Alkane 0.37 0.37 f 0.34 1 0.34 C16 AlXane 0.31 , 0.35 1 0.33 0.33 Unknown Compounds ' I j 1 to 6 1.34 1 1.68 1.75 1.90 (C12 Me Ester +) 1.79* 1 0.06 0.10 0.04 C18 Alkane) 0.04 0.03 0.03 Unknowns 7+8 ~ 0.16 0.3 0.49 1 0.33 Unknowns 9+10. 0.87 trace trace trace C12 Alcohol. 57.30 56.97 55.86 54.33 C14 Me Ester0.21 trace trace trace --Unknowns 11 to 13 0.17 0.17 0.14 , 0.23 C14 Alcohol24.64 24.86 24.94 26.52 C16 Me Ester0.09 trace trace trace Unknowns 14+15 0.14 0.Q3 0.03 0.08 C16 Alcohol , 9.45 9.42 9.66 9.47 C18 Me Ester 1 0.23 0.02 0.03 0.03 Unknown 161 0.05 trace trace , trace ,C18 Alcohol0.35 0.45 0.50 ~ 0.46 'Wax Esters:
~a) C12 ~ C12 _ 2.78 2.60 , 3.20 (b) C12 ~ C14_ 1.42 1.72 1 1.68 5c) C12 ~ C16_ 0.75 0.80 ' 0.67 (d) C14 ~ C14 trace trace 0.08 * Components not resolved.
: ~ ' --... . .
,. - , .:
.: . :
WOso~oR123 PCT/GB90/00065 20~47 In Table 2 the wax esters are identified variously as (a) C12 ~ C12, (b) C12 ~ C14~ (c) C12 C16 and (d) C14 C14. These materials are thought, by reason of their gas chromatographic retention times, to represent respectively:
(a) the ester of a C12 alkanol with a C12 fatty acid;(b) mixture of esters of a C12 alkanol with a C14 fatty acid and of a C14 alkanol with a C12 fatty acid;
(c) mixture of esters of a C12 alkanol with a C16 fatty acid and of a C16 alkanol with a C12 fatty acid; and (d) the ester of a C14 alkanol with a C14 fatty acid.The results plotted in Table 2 were obtained using a Pye Unicam 4500 Gas Chromatograph fitted with 25 metre long Nordian NB351 FAME capillary column and with a flame ionisation detector. The carrier gas was helium at a column inlet pressure of 2.39 bar. The sample injection volume was O.4 microlitres. The column was temperature ~rogrammed as as follows: 2 minutes at 80C after sample injection, followed by heating at 8C per minute to 230C, whereafter the temperature was maintained at this value. The injection port temperature was 250C and the detector temperature was -270C. A sample stream split ratio of 40 to 50:1 was used. ~;
It is clear from these results that, under the influence of the transesterification catalyst, the methyl esters of the ;
C12, C14, C16 and C18 fatty acids are smoothly converted to wax esters. It should be noted, however, that the gas chromatographic technique employed, although resolving the wax esters in total carbon number order, did not enable good resolution between wax esters containing the same number of carbon atoms. For example, the resolution achieved between a C12 ~ C16 wax ester and a C14 - C14 wax ester relatively poor.
ExamPle 2 665 grams of crude fatty alcohol product which had - - ,.
-. - - : :.
. , . ~ . .: -. :.
WO90/08123 PCT/GB90/~065 - 2~5 ~7 26 -been subjected to transesterification under the conditions outlined in Example 1 were distilled under vacuum in a simple laboratory distillation unit, the boiler of which was fitted with a short packed column to prevent droplet entrainment. The dimensions of the packed column were 2.5 cm diameter x 30 cm high, packed with 4 mm Raschig rings.
The results are summarised in Tables 3 and 4 below. The analysis figures of Table 4 are again expressed as % w/w.
The abbreviations used in Table 4 are the same as those used in Table 2.
Table 3 ._ . , ,~
~raction - Fore run Product Residue .
~ressure ~bar) ' 0.014 0.013 , 0.013 ~Temperature up to 141C , 141 - 170C Not . _ l distilled Weight (g) ¦ 96.1 ¦ 537.1 ¦ 30.0 - . .- ~ ;
. .
' .' WO9~/08123 PCT/GB90/~065 - 27 -20~5~7 Table 4 ANALYSIS
, Fraction Fore run Product ` Residue Methanol trace - -Unknown 1 0.84 ' - -C12 Alkane 1.22 0.04 Unknown 2 1.53 , - -C14 ~lkane 1.35 ', 0.21 Vnknown 3 : 0.91 .Unknown 4 0.17 C16 Alkane 0.47 , 0,33 Unknown 5 2.36 ,Unknown 6 i0.46 ; - i _ :
IC12 Me Ester ~
C18 Alkane 0 03 ! ol ; o . ol Unknown 7-10 j0.60 ~I0.40 ! 0 04 C12 Alcohol '75.34 l,59.66 ¦ 0.30 C14 Me Ester trace Unknown 11-12 0.11 ¦ 0.2 C14 ~lcohol 1,10.24 129.51 ! 1.50 C16 Me Ester 10.03 -Unknown 13 trace trace trace Unknown 14-15 0.01 _ C16 ~lcohol 3.16 8.91 6.86 Cl~ Me Ester 0.09 _ _ :
C18 Alcohol 10.29 0.06 0.88 Wax Esters:
C12 ~ C12 0.02 _ 0.37 Other wax esters 0.28 0.8 81.66 Other unknowns 0.09 _ 8.36 _ :- . , - : ,- ~ ~ . . , -. ~ .. .
.. ...
wo ~/n8t2~ PCT/GB90/00065 2~5~4~
Because the transesterification catalyst remained active throughout the distillation and because the lower alcohois were progressively removed from the system by the distillation procedure, the wax esters remaining in the distillation residue were of higher molecular weight than in the starting material. In other words there was continuous ~-ester interchange amongst the wax esters during distillation with a progressive loss of the more volatile fatty alcohol components to the distillate.
Example 3 The distillation residue of Tables 3 and 4 was divided into two portions. One portion was heated to 180C
for 2 hours with methanol at a methanol:wax ester mole ratio of 20:1 and the other portion was heated at the same temperature and for the same time but at a methanol:wax ester ratio of 40:1. Upon quench cooling, analyses in % w/w were obtained, using the gas chromatographic technique of Example 2, as set out in Table 5 below. The abbreviations in Table 5 are the same as are used in Tables 2 and 4. The analytical figures are expressed on a methanol free basis.
,:
-:.
- .~ , woso~oX123 PCT/G890/~065 - 29 ~ 2 0 ~ 7 Table 5 -Portion No. 1 2 C12 Me ester 32.94 34.56 C12 Alcohol 0.17 0.13 ~C14 Me ester 4.48 4.88 1 -C14 Alcohol 2.54 2.43 C16 Me ester 0.56 0.62 C16 Alcohol 41.27 1 42.75 jC18 Me ester 0.33 ¦ trace 1-'C18 Alcohol 7.85 1 8.16 Wax esters l(a) Cl2-cl2 0.02 I trace l(b) C12-C14 0.27 ¦ 0.33 c) Cl2-cl6 1 5.17 ¦(d) C14-C14 ; 2.52 ¦ . 0.98:
It can be seen from these results that, in comparison with the composition of the residue of Table 4, treatment with methanol has effected a considerable conversion of the wax esterS to C12- C14t C16 and C18 fatty alcohols and to the methyl esters of C12, C14, C16 and C18 fatty acids. This conversion has, moreover, been effected without the addition of further alkyl titanate transesterification catalyst, thus demonstrating that the transesterification catalytic activity has survived the vacuum distillation step of Example 2.
, . . . .
: .
.
.
It would be desirable to provide a method enabling fatty alcohol products obtained by hydrogenation of esters to be purified by distillation, even though such products contain appreciable proportions of unconverted esters. The existence of such a method would enable hydrogenation of the ester feedstock to be carried out under relatively mild conditions with less formation of byproduct alkane and hence with higher yields of alcohol products than can be obtained by conventional methods of manufacture of fatty alcohols by this route.
The present invention accordingly seeks to provide an improved process for refining alcohols produced by hydroqenation of esters, such as methyl esters produced by transesterification of natural glycerides or by :.
esterification of fatty acids produced by hydrolysis of such triglycerides, wherein the crude hydrogenation product still contains a minor amount of unconverted ester starting material. It further seeks to provide an improved process for production of fatty alcohols from fatty alcohol fractions obtained by hydrogenation of low molecular alkyl -esters, especially methyl esters, of fatty acids derived from natural triglycerides, under conditions which minimise fonmation of byproduct alkanes and ethers followed by refining of the resulting ester containing hydrogenation .. .. .. .
~ . ~
wo ~/08123 PCT/GB90/~065 _ 7 _ ` 20~5~7 product.
According to the present invention there is provided a process for the recovery of a fatty alcohol or alcohols from a fatty alcohol fraction containing a major molar amount of at least one fatty alcohol and a minor molar amount of at least one lower alkyl fatty acid ester, which process comprises:
(a) subjecting the fatty alcohol fraction to transesterifica~ion in the presence of a transesterification catalyst in a first transesterification zone maintained under transesterification conditions, thereby to convert substantially all of any lower alkyl fatty acid ester present in the feed mixture by ester intexchange with a corresponding amount of fatty alcohol or alcohols to lower alkanol and to a wax ester derived from a fatty alcohol and a fatty acid;
~b) separating resulting lower alkanol-from the reaction mixture of step ta1 by vaporisation to yield an intermediate transesterification product mixture that is at least partially free from lower alkanol and contains a fatty alcohol or alcohols and a wax ester or esters:
(c) distilling fatty alcohol or fatty alcohols and wax ester or wax esters of the intermediate transesterification product mixture of step (b) to yield (i) an overhead fraction that contains the fatty alcohol or alcohols and is substantially free from lower alkyl fatty acid ester, and ~ii) a distillation residue comprising fatty alcohol or alcohols, and wax ester or esters;
(d) subjecting the distillation residue of step (c) to transesterification in the presence of added lower alkanol and of a transesterification catalyst in a second transesterification zone maintained under transesterification conditions, thereby to reconvert wax ester or esters to lower alkyl fatty acid ester or esters and to fatty alcohol or alcohols;
' ' -:.
WO90/08123 PCT/GB90/0006~
S~4~ - 8 -te) evaporating unreacted lower alkanol from the reacti-n mixture of step (d) to yield a liquid residue that is substantially free from lower alkanol; and ~f) distilling fatty alcohol or alcohols and lower alkyl fatty acid ester or esters of the liquid residue of step te) to produce (i) an overhead product containing a mixture of a lower alkyl fatty acid ester or esters and fatty alcohol or alcohols and (ii) a relatively involatile residue.
In another aspect the invention provides a process for the production of fatty alcohols which comprises hydrogenating a lower alkyl fatty acid ester or esters in a hydrogenation zone containing a charge of a hydrogenation catalyst and maintained under hydrogenation conditions to yield a mixture of (i) lower alkanol And (ii) a fatty alcohol fraction containing a fatty alcohol or alcohols and a minor amount of unreacted lower alkyl fatty acid ester or esters; and which further comprises:
(a) subjecting the fatty alcohol fraction to transesterification in the presence of a transesterification catalyst in a first transesterification zone maintained under transesterification conditions, thereby to convert substantially all of any lower alkyl fatty acid ester present in the feed mixture by ester interchange with a corresponding amount of fatty alcohol or alcohols to lower alkanol and to a wax ester derived from a fatty alcohol and a fatty acid;
tb) separating resulting lower alkanol from the reaction mixture of step (a) by vaporisation to yield an intermediate transesterification product mixture that is at least partially free from lower alkanol and contains a fatty alcohol or alcohols and a wax ester or esters;
(c) distilling fatty alcohol or fatty alcohols and wax ester or wax esters of the intermediate transesterification product mixture of step (b) to yield ti) an overhead ,. . .
.
WO90/0812~ PCT/GB90/00065 9 ~ 5 ~ 7 fraction that contains the fatty alcohol or alcohols and is substantially free from lower alXyl fatty acid ester, and (ii) a distillation residue comprising fatty alcohol or alcohols, and wax ester or esters;
(d) subjecting the distillation residue of step (c) to transesterification in the presence of added lower alkanol and of a transesterification catalyst in a second transesterification zone maintained under transesterification conditions, thereby to reconvert wax ester or esters to lower alkyl fatty acid ester or esters and to fatty alcohol or alcohols:
(e) evaporating unreacted lower alkanol from the reaction mixture of step (d) to yield a liquid residue that is substantially free from lower alkanol;
(f) distilling fatty alcohol or alcohols and lower alkyl fatty acid ester or esters of the liquid residue of step (e) to produce (i) an overhead product containing a mixture of a lower alkyl fatty acid ester or esters and fatty alcohol or alcohols and (ii) a relatively involatile residue; and (g) recycling material of the overhead product of step (f) to thP hydrogenation step.
In this specification the term "fatty alcohol"
means an alkanol, preferably a linear alkanol, containing from about 6 to about 26 carbon atoms. Preferred fatty alcohols contain from about lO to about 20 carbon atoms.
Typical fatty alcohols include l-decanol, l-dodecanol, l-tetradecanol, l-hexadecanol, l-octadecanol, l-octadecenol and the like, and mixtures thereof. The term "lower alkyl"
means Cl- to C4-alkyl, including methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl and sec-butyl. The preferred lower alkyl radical is methyl. Similarly the term "lower alkanol" embraces Cl to C4 alkanols, including m~thanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, and sec-butanol. Methanol is the preferred lower alkanol.
. . .. .
, .
. . .
WO90/~8123 PCT/GB90/00065 ` 20~5547 - lO -By the term "~atty acids" we mean alkyl or alkenyl carboxylic acids, preferably linear alkyl or alkenyl carboxylic acids, containing from about Ç to about 26 carbon atoms, preferably about 10 to about 20 carbon atoms.
Examples of such fatty acids are decanoic acid (capric acid), dodecanoic acid tlauric acid), tetradecanoic acid (myristic acid), pentadecanoic acid, hexadecanoic acid (palmitic acid), heptadecanoic acid (margaric acid), octadecanoic acid (stearic acid or isostearic acid), oct~decenoic acids (oleic acid, linoleic acid or linolenic acid), eicosanoic acid (arachidic acid) and docosanoic acid (behenic acid). Mixtures of fatty acids are of especial importance as raw materials from which the lower alkyl ~atty acid esters used as starting material in the hydrogenation step are prepared. Such mixtures of acids can be obtained by hydrolysis of naturaily occurring triglycerides such as coconut oil, rape seed oil~ palm oils, tallowt lard and fish oil. If desired, such mixtures of acids can be subjected to distillation to remove lower boiling acids having a lower boiling point than a chosen temperature and thus produce a "topped" mixture of acids,-to remove higher boiling acids having a boiling point higher than a second chosen temperature and thus produce a ltailed" mixture of acids, or to remove both lower and higher boiling acids and thus produce a l! topped and tailed" mixture of acids.
In the hydrogenation of lower alkyl fatty acid esters there can be used vapour phase hydrogenation conditions in which the composition of the gas stream is selected so that at all times the material in contact with the hydrogenation catalyst is above the dew point, preferably at least about 5C above the dew point. Suitable hydrogenation catalysts include known ester hydrogenation catalysts such as reduced copper oxide-zinc oxide (see GB-B-2116552), and copper chromite, and promoted copper chromite catalysts. The preferred catalysts are reduced wo9o~n812~ PCT/CB90/00065 11- 20~ 7 copper oxide-zinc oxide catalysts of the type disclosed in GB-B-2116552. The preferred copper chromite catalysts are those containing from about 25 to about 45 percent by weight of copper and from about 20 to about 35 percent by weight of chromium, calculated as metal. Typical hydrogenation conditions include use of temperatures of up to about 260C, such as temperatures in the range of from about 140C to about 240C, and pressures in the range of from about 5 bar to about 100 bar. Liquid phase hydrogenation conditions can alternatively be used, if desired, for production of a fatty alcohol fraction by hydrogenation of a lower alkyl fatty acid ester or esters. In liquid phase hydrogenation typical operating conditions include use of a temperature of from about 180C to about 300C and a pressure of from about 50 bar to about 300 bar.
The hydrogenation mixture obtained by hydrogenating a lower alkyl fatty acid ester or mixture of esters contains, in addition to a fatty alcohol or fatty alcohol mixture, also lower alkanol, such as methanol. The methanol or other lower alkanol is separated in any known manner, as by distillation in one or more stages, from the fatty alcohol or alcohols to yield a fatty alcohol fraction suitable for use in the process of the invention. Such a fatty alcohol fraction typically contains, besides possibly a minor molar amount of methanol or other lower alkanol (usually less than about 5 mole %), a major molar amount of a fatty alcohol or alcohols (usually about 90 mole % or more) and a minor molar amount of unreacted lower alkyl fatty acid ester or esters (usually less than about 5 mole % ) .
In transesterification step (a~ the fatty alcohol fraction is subjected to transesterification in the presence of a transesterification catalyst. Any known transesterification catalyst may be used. Examples include alkyl titanates, alkali metal alkoxides, and metallic tin : ~ .
, Wo ~/0812~ PCT/GB90/~065 20~ 7 - 12 -and stannous hydroxide. Although acids, such as sulphuric acid and sulphonic acids, have been proposed as liquid phase transesterification catalysts in the prior art, the use of such catalysts is best avoided since there is a risk of the fatty alcohol product becoming contaminated with sulphurous impurities. Other transesterification catalyst systems which have been proposed, but are not preferred, include bases, compounds of alkali and alkaline earth metals, water, and metals such as zinc, cadmium, lead and their compounds.
It is also contemplated that acidic resins containing, for example, -SO3H and/or -COOH groups or basic resins containing, for example, basic substituted ammonium groups can be used as transesterification catalysts.
A particularly preferred class of transesterification catalyst is the alkyl titanates. Any alkyl titanate may be added as catalyst but, as the alkyl titanate will itself participate in ester interchange, the alkoxide radicals originally present in the alkyl titanate will tend to undergo exchange with alkoxide radicals derived from the fatty alcohol or alcohols during the operation of the process of the invention.
Another particularly preferred class of transesterification catalyst is the alkali metal alkoxides, such as sodium methoxide or sodium ethoxide. Again exchange of alkoxide radicals in the catalyst with alkoxide radicals derived from the fatty alcohol or alcohols will tend to occur with time in the first transesterification zone.
Alternatively there may be used an alkali metal alkoxide derived from the fatty alcohol product itself, or from one or more of them if a mixture of fatty alcohols is to be prodllceq .
The transesterification conditions used in step (a) will to a large extent depend upon the activity of the transesterification catalyst. Although the use of elevated pressures is not ruled out, it will normally be preferred to .:
...-: .. -; :, : ....
:, .
WosO/081~3 PCT/GB90/~065 '~0~5~7 operate at a substantially atmospheric pressure or below, for example a pressure in the range of from about 0.1 bar to about 1.2 bar. In this way the vaporisation of methanol or other lower alkanol of step (b) is facilitated during the course of the transesterification reaction of step (a).
Removal of the lower alkanol during transesterification drives the transesterification reaction towards completion.
When ~sing an alkyl titanate a temperature of up to about 240C, such as a temperature in the range of from about 120C to about 200C, is typically used, for example a temperature of from about 170C to about 1~0C. Alkali metal alkoxides enable use of lower operating temperatures, e.g. in the range of from about 40C to about 100C, but normally require introduction of extra processing steps as will be further explained below.
Similar transesterification catalysts and temperature conditions can be used in step (d). However, it will usually be preferred to employ in step (d) a superatmospheric pressure, for example a pressure of from about 1.~ bar to about 50 bar, in order to maintain the lower alkanol (e.g. methanol) in the liquid phase in the second transesterification zone.
As already mentioned steps (a) and (b) are preferably conducted simultaneously in a first transesterification zone that has provision for recovery overhead of the liberated lower alXanol.
An advantage of the use of an alkyl titanate as transesterification catalyst is that the subsequent distillation and/or evaporation steps ~i.e. step (c) and steps (e) and (f)) can be conducted without prior removal of the catalyst. However, when using an alkali metal alkoxide as transesterification catalyst, it is preferable to neutralise the catalyst prior to distillation and/or evaporation. Conveniently this neutralisation step can be effected by passing the catalyst containing material through .
WO90/08123 PCT/GB90/0~65~
20~554~ - 14 -a bed of an ion exchange resin containing -SO3H and/or -COOH
groups, thus removing the alkali metal from the liquid mixture:
R- SO3 H + NaOR' = RSO3Na + HOR ', where R represents the resin and -OR ' represents an alkoxide radical.
A further advantage of the use of alkyl titanates is that the catalyst remaining in the relatively involatile residue of step (f) can be used to form at least a part of the transesterification catalyst used in step ~a). The balance of any amount of catalyst required can then be supplied by make up alkyl titanate. Control of "heavies" in the process can be achieved by purging a part of the relatively involatile residue of step ~f); the remainder of this relatively involatile residue can be recycled for use in step (a).
When using an alkali metal hydroxide as transesterification catalyst, on the other hand, there will usually be no residual catalyst in the relatively involatile residue of step (f) as neutralisation will usually be practised prior to any distillation step. Similarly, if a resin catalyst is used as a transesterification catalyst, there will be no catalyst dissolved in the relatively involatile residue of step (f). Hence recycle of the relatively involatile residue has no benefit in these cases and the relatively involatile residue of step (f) can be purged from the plant and used as fuel.
If an alkyl titanate transesterification catalyst is used, steps (e) and (f) can be carried out without prior removal of the catalyst. In this case it is best to operate with as short residence times as possible in these steps so as to minimise the risk of substantial reversion of the transesterification reaction with consequent re-formation of wax esters in these steps. Hence it is preferred to effect step ~e) by flash distillation so as to minimise the ..~ . ~ , ~ , .
.
w~o/n812~ PCT/GB90/00065 - 15 - 2~55(~'7 residence time in this step and to ef~ect step (f), for similar reasons, in a falling film or wiped film evaporator.
Distillation steps (c) and (f) are normally effected at or near atmospheric pressure or below, for example at a pressure in the range of from about 0.005 bar to about 1.2 bar.
In order that the invention may be clearly understood and readily carried into effect two preferred forms of alcohol production plant designed to operate according to the teachings of the present invention will now be described, by way of example only, with reference to the accompanying drawings, Figures 1 and 2 of which are each a flow diagram of a respective plant.
It will be understood by those skilled in the art that the drawings are diagrammatic and that further items of equipment such as reflux drums, pumps, vacuum pumps, temperature sensors, pressure sensors, pressure relief valves, control valves, flow controllers, level controllers, holding tanks, storage tanks, and the like may additionally be required in a commercial plant. The provision of such ancillary items of equipment forms no part of the present invention and is in accordance with conventional chemical engineering practice.
Referring to Figure 1, a hydrogenation plant 1 is supplied in line 2 with a feed ester stream, in line 3 with recycled material, and in line 4 with a hydrogen stream.
The feed ester stream in line 1 is a mixture of methyl esters obtained by esterification of a fatty acid mixture obtained by hydrolysis of coconut oil, followed by "topping and tailing~. This fatty acid mixture contains approximately 65 mole % dodecanoic acid, 25 mole %
tetradecanoic acid and 10 mole % hexadecanoic acid.
~ ydrogenation plant 1 can operate using any suitable ester hydrogenation process and with any suitable ester hydrogenation catalyst. A reduced copper oxide-zinc " , . . . ~, . . .
..
~: ' :: ~ , ; -~, ~
woso/oxli~ PCT/GB90/0006~
2~5~ - 16 -oxide catalyst of the type disclosed in GB-B-2116552 is an example of a suitable hydrogenation catalyst. Plant 1 may include one or more hydrogenation stages, as well as a preliminary distillation zone for separating at least a major part of the by-product methanol. The hydrogen stream in line 2 is produced in conventional manner from synthesis gas followed by a water gas shift reaction, CO2 removal and, if desired, further purification by pressure swing absorption. It may contain one or more inert gases, such as nitrogen, methane and argon. The byproduct methanol can be recycled for production of further methyl esters in line 5. A purge gas stream is taken from hydrogenation plant 1 in line 6. Hydrogenation plant 1 can operate using a vapour phase regime in which the reaction mixture in contact with the catalyst is always above its dew point. Alternatively it may be operated using a liquid phase regime, in which case a copper chromite catalyst will usually be preferred.
A crude fatty alcohol stream is recovered from plant 1 in line 7. This contains a minor amount of unconverted methyl esters, besides minor amounts of by-product alkanes, unknowns and "heavies". The crude fatty alcohol stream passes through heat exchanger 8 in which its temperature is adjusted to about 160C to about 200C, preferably about 170C to about 190C, e.g. 190C. The hot stream in line 9 is admixed with a mixture of fresh and recycled ester interchange catalyst ~transesterification catalyst), e.g. an alkyl titanate, supplied in line 10 and passes into a first ester interchange reactor 11 which provides a first transesterification zone. Reactor 11 is designed so as to provide a residence time therein in the range of f rom about 10 minutes up to about 120 minutes, preferably from about 15 minutes to about 60 minutes. ~he length of the residence time depends upon the temperature of the stream in line 9 and in react~r 11, as well as the effectiYe concentration of the alkyl titanate supplied in .
"` . : ~ .
, WOso/08123 PCT~GB90~065 2 0 ~ 7 line lO. In reactor ll the methyl esters of the fatty acids present in the feed stream in line 7 are converted to wax esters, i.e. fatty alcohol esters of the acid moieties of the methyl esters, by transesterification of the methyl esters with product fatty alcohols. Most of the methanol formed by transesterification is recovered as a vapour in line 12 from the vapour space in vessel ll and can be condensed and recycled to the methyl ester production plant (not shown).
The product from the first ester interchange reactor ll contains, besides a major molar amount of product alcohols, also minor molar amounts of alkane by-products, wax esters and "heavies", as well as traces of methanol. It is passed via line 13 into a product column 14 which is provided with three beds of structured packing 15, 16 and 17. Light ends, consisting mainly of alkane by-products, as well as traces of methanol, are recovered overhead in line 18 and are condensed by means of condenser l9. The resulting condensate in line 20 accumulates in reflux drum 21 which is vented to a vacuum pump (not shown) operating at 0.005 bar by line 22. Some alkanes are returned to product column 13 via line 23, pump 24 and line 25 to provide a reflux stream, whilst the net production of alkanes passes via line 26 to storage.
Product alcohols are withdrawn as vapour from product column 14 in line 27 and are condensed by means of condenser 28. The condensate passes on in line 29 to product drum 30 which is vented to a vacuum unit ~not shown) by line 31. Liquid product alcohols are passed via line 32, pump 33 and line 34 to product storage.
Bottoms product is withdrawn from product column 14 in line 35 and passed via line 36 to a falling film reboiler 37 which is operated at a temperature in the range of from about 210C to about 245~C, e.g. 240C. Part of the bottoms product is withdrawn in line 38 and is pumped by .. . .. ... . ., ~, . . . ., : ~
' - , . ~ ,' I ~- ~ ,, :. . ~ , 204~ 18 -pump 39 via line 40 to heat exchanger 41. Prior to entry to heat exchanger 41 excess methanol from line 42 is admixed with this part of the bottoms product. The quantity of methanol admixed via line 42 is typically at least about 5 times the stoichiometric quantity equivalent to the wax esters present in the bottom product up to about 100 times this stoichiometric quantity, for example about 80 times the stoichiometric quantity. In this way the equilibrium between wax esters and methanol, on the one hand, and methyl fatty acid esters, fatty alcohol and excess methanol, o~ the other hand, is shifted away from wax ester formation towards methyl fatty acid ester formation.
In heat exchanger 41 the temperature of the mixture of methanol and bottoms product, which still contains alkyl titanate transesteri~ication catalyst, is adjusted. The mixture passes on via line 43 to a second ester interchange reactor 44 which provides a second transesterification zone and is designed to provide a residence time of from about 30 minutes to about 240 minutes, preferably from about 60 minutes to about 180 minutes, e.g. about 120 minutes. The temperature in reactor 44 lies in the range of from about 160C to about 195C e.g.
about 180C. The size, and hence the residence time, selected for reactor 44 should be sufficient to allow the ester interchange to proceed to equilibrium at the temper~ture selected. The pressure in reactor 44 is typically about 42 bar. From second ester interchange reactor 44 the resulting transesterification product mixture is fed via line 45 through a pressure let down valve 46 to reduce its pressure to about 1.3 bar. It then continues in line 47 to a heated flash vessel 48. Methanol vapour is recovered overhead in line 49 and is condensed by means of a condenser ~not shown) for reuse elsewhere in the plant or for manufacture of further methyl esters.
The residual liquid phase exits flash column 48 in WO90/08l23 PCT/GB90/00065 2 ~ 7 line 50 and is pumped by pump 51 through line 52 via a pressure let down valve (not shown) to falling film evaporator 53 which is operated at a maximum temperature of about 240C and at a pressure of about 0.005 bar. A mixture of vapour and liquid exits falling film evaporator 53 in line 54 and passes into separation drum 55. The vapour is recovered in line 56 and condensed by condenser 57. The resulting condensate is passed in line 5~ to drum 59 which is connected to a vacuum system (not shown) by line 60. The liquid condensate, which comprises a mixture of product fatty alcohols, methyl esters, some methanol and traces of by-products, is recovered in line 61 and pumped by pump 62 .
to form the recycle stream in line 3.
The liquid from drum 55 is passed by line 63 and pump 64 either for waste disposal via line 65 or for recycle via line 66 to line 10.
Fresh alkyl titanate transesterification catalyst can be added as required via line 67.
The approximate flow rates of various of the streams expressed in molar units are summarised in Table 1 below:
.. ~ , , WO 90/08123 PCI`/GB90/00065 _ 20 -~o~547~ 3 ~ c ~ 3 t~
r 3 1~ tl) ~-~ x ;~ ~ ~ ~ :1 t~ 5 Pl 3 D) tt r~ 5 ~ O ~D 3 ~ <
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WO~0/08l2~ PCT/GB90/~065 - 21 - 204~5~7 Figure 2 illustrates a modified form of the plant of Figure l which is designed to operate using an alkali metal alkoxide as the transesterification catalyst in place of an alkyl titanate. In Figure 2 like reference numerals have been used to indicate similar parts to those illustrated in Figure l.
The temperature of the crude fatty alcohol stream in line 7 is adjusted to 45C in heat exchanger 8. A
solution containing 10% w/v of sodium methoxide in dry methanol is added in line lOl so as to provide a concentration of 0.05% w/v of sodium methoxide in the material flowing in line 102. In this plant first ester interchange reactor 11 is designed to provide, typically, a residence time therein of about 30 minutes. The material exiting reactor ll in line 13 is then passed through a bed 103 of ion exchange resin in vessel 104 to neutralise the catalyst. The ion exchange resin of bed 103 can contain sulphonic acid and/or carboxylic acid groups. The catalyst free stream passes on in line 105 to product column 14.
Removal of the sodium methoxide catalyst prior to distillation in product column 14 is desirable so as to obviate the formation of condensation by-products and dark coloured organic tars, which would be promoted by the presence of sodium methoxide in the mixture at the elevated temperatures prevailing in the product column 14.
Recovery of product alcohol in product column 14 -is effected in the same way as for the plant of Figure 1.
The bottom product in lines 35, 38 and 40 is then cooled to about 50C in heat exchanger 41. A similar stoichiometric exc~ss of methanol is added from line 106 to the liquid stream in line 43. The resulting mixture in line 107 is -then admixed with a 10~ w/v solution of sodium methoxide in dry methanol supplied by way of line 108 at a rate sufficient to provide a concentration of about 0.05% w/v ~-sodium methoxide in the mixed stream in line 109 before ... ~ . . . .
.
- : , , ' ~
: - . , '' ' ' PCrtGB90/00065 w~/081~
~o~5~7 - 22 -entry to sec~nd ester interchange reactor 44 which is designed for a residence time of about 120 minutes. The interchanged product stream in line 45 is then passed through a second bed 110 of ion exchange resin, which contains, for example, sulphonic acid groups and/or carboxylic acid yroups, in vessel lll. This removes sodium ions from the liquid phase and neutralises the sodium methoxide transesterification catalyst. The neutralised liquid phase passes on in line 112 to flash column 48.
As the material in line 112 contains no transesterification catalyst there is no need to recycle "heavies" via line 66 (as in the plant of Figure 1).
Moreover, as there is no catalyst remaining in the material in line 112, the risk of reversion of methyl esters to wax esters and loss of methanol vapour in columns 48 and 53 by ester interchange with fatty alcohols product is obviated.
In a modification of the plant of Figure 2 columns 48 and 53 are replaced by a batch still (not shown). In this case the material in line 112 is collected until there is sufficient to justify operating the batch still.
The invention is further illustrated in the following Examples.
Example l A crude fatty alcohol product containing a minor amount of unconverted fatty acid methyl esters was prepared by hydrogenating in a laboratory hydrogenation reactor under vapour phase conditions (i.e. under conditions such that the reaction mixture in contact with the catalyst was at all times above its dew point) a mixture of fatty acid methyl esters obtained from a "topped and tailed" fatty acid mixture produced by hydrolysis of coconut oil. The catalyst used was a reduced copper oxide-zinc oxide ester hydrogenation catalyst. Prior to use the crude alcohol product mixture was distilled to remove substantially all the methanol produced as coproduct in the hydrogenation - - , , .
.
. .
Wo ~/0812~ PCT/GB90/00065 - 23 - 20~
step.
Three samples of the substantially methanol free crude fatty alcohol product were each heated to 200C under a nitrogen atmosphere for 30 minutes at 0.99 bar with 0.03%
w/w of Tilcom BIP (trade mark of Tioxide Chemical Division of British Titan Products p.l.c.). This material is reported to be a mixed lso-propyl/n-butyl titanate.
Subsequent analysis showed that, in the presence of a large excess of fatty alcohols and under conditions allowing methanol to escape from the reaction system, substantially all of the methyl esters had been transformed into wax esters. The results are plotted in Table 2 below which indicates the amounts of the components present in % w/w.
In Table 2 "C12 Me ester" means methyl dodecanoate, whilst "C14 Me ester", "C16 Me ester", and "C18 Me ester" represent respectively the corresponding methyl esters of the C14, C16 and C18 carboxylic acids. There were detected sixteen unidentified compounds, listed as "Unknowns 1 to 16" in Table 2, in minor or trace amounts. -~
. ~ , ... . .. . . . . . .
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WOs~/08123 PCT/GB90/~065 5 ~ 4~7 Table 2 _.. .. . .. _ _ COMPONENT FEED I R~n 1 , Run 2 Run 3 Methanol 2.19 l 0.03 ~ 0.11 1 0.02 C12 Alkane 0.34 ¦ 0.27 1 0.20 j 0.24 C14 Alkane 0.37 0.37 f 0.34 1 0.34 C16 AlXane 0.31 , 0.35 1 0.33 0.33 Unknown Compounds ' I j 1 to 6 1.34 1 1.68 1.75 1.90 (C12 Me Ester +) 1.79* 1 0.06 0.10 0.04 C18 Alkane) 0.04 0.03 0.03 Unknowns 7+8 ~ 0.16 0.3 0.49 1 0.33 Unknowns 9+10. 0.87 trace trace trace C12 Alcohol. 57.30 56.97 55.86 54.33 C14 Me Ester0.21 trace trace trace --Unknowns 11 to 13 0.17 0.17 0.14 , 0.23 C14 Alcohol24.64 24.86 24.94 26.52 C16 Me Ester0.09 trace trace trace Unknowns 14+15 0.14 0.Q3 0.03 0.08 C16 Alcohol , 9.45 9.42 9.66 9.47 C18 Me Ester 1 0.23 0.02 0.03 0.03 Unknown 161 0.05 trace trace , trace ,C18 Alcohol0.35 0.45 0.50 ~ 0.46 'Wax Esters:
~a) C12 ~ C12 _ 2.78 2.60 , 3.20 (b) C12 ~ C14_ 1.42 1.72 1 1.68 5c) C12 ~ C16_ 0.75 0.80 ' 0.67 (d) C14 ~ C14 trace trace 0.08 * Components not resolved.
: ~ ' --... . .
,. - , .:
.: . :
WOso~oR123 PCT/GB90/00065 20~47 In Table 2 the wax esters are identified variously as (a) C12 ~ C12, (b) C12 ~ C14~ (c) C12 C16 and (d) C14 C14. These materials are thought, by reason of their gas chromatographic retention times, to represent respectively:
(a) the ester of a C12 alkanol with a C12 fatty acid;(b) mixture of esters of a C12 alkanol with a C14 fatty acid and of a C14 alkanol with a C12 fatty acid;
(c) mixture of esters of a C12 alkanol with a C16 fatty acid and of a C16 alkanol with a C12 fatty acid; and (d) the ester of a C14 alkanol with a C14 fatty acid.The results plotted in Table 2 were obtained using a Pye Unicam 4500 Gas Chromatograph fitted with 25 metre long Nordian NB351 FAME capillary column and with a flame ionisation detector. The carrier gas was helium at a column inlet pressure of 2.39 bar. The sample injection volume was O.4 microlitres. The column was temperature ~rogrammed as as follows: 2 minutes at 80C after sample injection, followed by heating at 8C per minute to 230C, whereafter the temperature was maintained at this value. The injection port temperature was 250C and the detector temperature was -270C. A sample stream split ratio of 40 to 50:1 was used. ~;
It is clear from these results that, under the influence of the transesterification catalyst, the methyl esters of the ;
C12, C14, C16 and C18 fatty acids are smoothly converted to wax esters. It should be noted, however, that the gas chromatographic technique employed, although resolving the wax esters in total carbon number order, did not enable good resolution between wax esters containing the same number of carbon atoms. For example, the resolution achieved between a C12 ~ C16 wax ester and a C14 - C14 wax ester relatively poor.
ExamPle 2 665 grams of crude fatty alcohol product which had - - ,.
-. - - : :.
. , . ~ . .: -. :.
WO90/08123 PCT/GB90/~065 - 2~5 ~7 26 -been subjected to transesterification under the conditions outlined in Example 1 were distilled under vacuum in a simple laboratory distillation unit, the boiler of which was fitted with a short packed column to prevent droplet entrainment. The dimensions of the packed column were 2.5 cm diameter x 30 cm high, packed with 4 mm Raschig rings.
The results are summarised in Tables 3 and 4 below. The analysis figures of Table 4 are again expressed as % w/w.
The abbreviations used in Table 4 are the same as those used in Table 2.
Table 3 ._ . , ,~
~raction - Fore run Product Residue .
~ressure ~bar) ' 0.014 0.013 , 0.013 ~Temperature up to 141C , 141 - 170C Not . _ l distilled Weight (g) ¦ 96.1 ¦ 537.1 ¦ 30.0 - . .- ~ ;
. .
' .' WO9~/08123 PCT/GB90/~065 - 27 -20~5~7 Table 4 ANALYSIS
, Fraction Fore run Product ` Residue Methanol trace - -Unknown 1 0.84 ' - -C12 Alkane 1.22 0.04 Unknown 2 1.53 , - -C14 ~lkane 1.35 ', 0.21 Vnknown 3 : 0.91 .Unknown 4 0.17 C16 Alkane 0.47 , 0,33 Unknown 5 2.36 ,Unknown 6 i0.46 ; - i _ :
IC12 Me Ester ~
C18 Alkane 0 03 ! ol ; o . ol Unknown 7-10 j0.60 ~I0.40 ! 0 04 C12 Alcohol '75.34 l,59.66 ¦ 0.30 C14 Me Ester trace Unknown 11-12 0.11 ¦ 0.2 C14 ~lcohol 1,10.24 129.51 ! 1.50 C16 Me Ester 10.03 -Unknown 13 trace trace trace Unknown 14-15 0.01 _ C16 ~lcohol 3.16 8.91 6.86 Cl~ Me Ester 0.09 _ _ :
C18 Alcohol 10.29 0.06 0.88 Wax Esters:
C12 ~ C12 0.02 _ 0.37 Other wax esters 0.28 0.8 81.66 Other unknowns 0.09 _ 8.36 _ :- . , - : ,- ~ ~ . . , -. ~ .. .
.. ...
wo ~/n8t2~ PCT/GB90/00065 2~5~4~
Because the transesterification catalyst remained active throughout the distillation and because the lower alcohois were progressively removed from the system by the distillation procedure, the wax esters remaining in the distillation residue were of higher molecular weight than in the starting material. In other words there was continuous ~-ester interchange amongst the wax esters during distillation with a progressive loss of the more volatile fatty alcohol components to the distillate.
Example 3 The distillation residue of Tables 3 and 4 was divided into two portions. One portion was heated to 180C
for 2 hours with methanol at a methanol:wax ester mole ratio of 20:1 and the other portion was heated at the same temperature and for the same time but at a methanol:wax ester ratio of 40:1. Upon quench cooling, analyses in % w/w were obtained, using the gas chromatographic technique of Example 2, as set out in Table 5 below. The abbreviations in Table 5 are the same as are used in Tables 2 and 4. The analytical figures are expressed on a methanol free basis.
,:
-:.
- .~ , woso~oX123 PCT/G890/~065 - 29 ~ 2 0 ~ 7 Table 5 -Portion No. 1 2 C12 Me ester 32.94 34.56 C12 Alcohol 0.17 0.13 ~C14 Me ester 4.48 4.88 1 -C14 Alcohol 2.54 2.43 C16 Me ester 0.56 0.62 C16 Alcohol 41.27 1 42.75 jC18 Me ester 0.33 ¦ trace 1-'C18 Alcohol 7.85 1 8.16 Wax esters l(a) Cl2-cl2 0.02 I trace l(b) C12-C14 0.27 ¦ 0.33 c) Cl2-cl6 1 5.17 ¦(d) C14-C14 ; 2.52 ¦ . 0.98:
It can be seen from these results that, in comparison with the composition of the residue of Table 4, treatment with methanol has effected a considerable conversion of the wax esterS to C12- C14t C16 and C18 fatty alcohols and to the methyl esters of C12, C14, C16 and C18 fatty acids. This conversion has, moreover, been effected without the addition of further alkyl titanate transesterification catalyst, thus demonstrating that the transesterification catalytic activity has survived the vacuum distillation step of Example 2.
, . . . .
: .
.
.
Claims (12)
1. A process for the recovery of fatty alcohol or alcohols from a fatty alcohol fraction containing a major molar amount of at least one fatty alcohol and a minor molar amount of at least one lower alkyl fatty acid ester, which process comprises:
(a) subjecting the fatty alcohol fraction to transesterification in the presence of a transesterification catalyst in a first transesterification zone maintained under transesterification conditions, thereby to convert substantially all of any lower alkyl fatty acid ester present in the feed mixture by ester interchange with a corresponding amount of fatty alcohol or alcohols to lower alkanol and to a wax ester derived from a fatty alcohol and a fatty acid;
(b) separating resulting lower alkanol from the reaction mixture of step (a) by vaporisation to yield an intermediate transesterification product mixture that is at least partially free from lower alkanol and contains a fatty alcohol or alcohols and a wax ester or esters;
(c) distilling fatty alcohol or fatty alcohols and wax ester or wax esters of the intermediate transesterification product mixture of step (b) to yield (i) an overhead fraction that contains the fatty alcohol or alcohols and is substantially free from lower alkyl fatty acid ester, and (ii) a distillation residue comprising fatty alcohol or alcohols, and wax ester or esters;
(d) subjecting the distillation residue of step (c) to transesterification in the presence of added lower alkanol and of a transesterification catalyst in a second transesterification zone maintained under transesterification conditions, thereby to reconvert wax ester or esters to lower alkyl fatty acid ester or esters and to fatty alcohol or alcohols;
(e) evaporating unreacted lower alkanol from the reaction mixture of step (d) to yield a liquid residue that is substantially free from lower alkanol; and (f) distilling fatty alcohol or alcohols and lower alkyl fatty acid ester or esters of the liquid residue of step (e) to produce (i) an overhead product containing a mixture of a lower alkyl fatty acid ester or esters and fatty alcohol or alcohols and (ii) a relatively involatile residue.
(a) subjecting the fatty alcohol fraction to transesterification in the presence of a transesterification catalyst in a first transesterification zone maintained under transesterification conditions, thereby to convert substantially all of any lower alkyl fatty acid ester present in the feed mixture by ester interchange with a corresponding amount of fatty alcohol or alcohols to lower alkanol and to a wax ester derived from a fatty alcohol and a fatty acid;
(b) separating resulting lower alkanol from the reaction mixture of step (a) by vaporisation to yield an intermediate transesterification product mixture that is at least partially free from lower alkanol and contains a fatty alcohol or alcohols and a wax ester or esters;
(c) distilling fatty alcohol or fatty alcohols and wax ester or wax esters of the intermediate transesterification product mixture of step (b) to yield (i) an overhead fraction that contains the fatty alcohol or alcohols and is substantially free from lower alkyl fatty acid ester, and (ii) a distillation residue comprising fatty alcohol or alcohols, and wax ester or esters;
(d) subjecting the distillation residue of step (c) to transesterification in the presence of added lower alkanol and of a transesterification catalyst in a second transesterification zone maintained under transesterification conditions, thereby to reconvert wax ester or esters to lower alkyl fatty acid ester or esters and to fatty alcohol or alcohols;
(e) evaporating unreacted lower alkanol from the reaction mixture of step (d) to yield a liquid residue that is substantially free from lower alkanol; and (f) distilling fatty alcohol or alcohols and lower alkyl fatty acid ester or esters of the liquid residue of step (e) to produce (i) an overhead product containing a mixture of a lower alkyl fatty acid ester or esters and fatty alcohol or alcohols and (ii) a relatively involatile residue.
2. A process for the production of fatty alcohol which comprises hydrogenating a lower alkyl fatty acid ester or esters in a hydrogenation zone containing a charge of a hydrogenation catalyst and maintained under hydrogenation conditions to yield a mixture of (i) lower alkanol and (ii) a fatty alcohol fraction containing a fatty alcohol or alcohols and a minor amount of unreacted lower alkyl fatty acid ester or esters; and which further comprises:
(a) subjecting the fatty alcohol fraction to transesterification in the presence of a transesterification catalyst in a first transesterification zone maintained under transesterification conditions, thereby to convert substantially all of any lower alkyl fatty acid ester present in the feed mixture by ester interchange with a corresponding amount of fatty alcohol or alcohols to lower alkanol and to a wax ester derived from a fatty alcohol and a fatty acid;
(b) separating resulting lower alkanol from the reaction mixture of step (a) by vaporisation to yield an intermediate transesterification product mixture that is at least partially free from lower alkanol and contains a fatty alcohol or alcohols and a wax ester or esters;
(c) distilling fatty alcohol or fatty alcohols and wax ester or wax esters of the intermediate transesterification product mixture of step (b) to yield (i) an overhead fraction that contains the fatty alcohol or alcohols and is substantially free from lower alkyl fatty acid ester and (ii) a distillation residue comprising fatty alcohol or alcohols, and wax ester or esters;
(d) subjecting the distillation residue of step (c) to transesterification in the presence of added lower alkanol and of a transesterification catalyst in a second transesterification zone maintained under transesterification conditions, thereby to reconvert wax ester or esters to lower alkyl fatty acid ester or esters and to fatty alcohol or alcohols;
(e) evaporating unreacted lower alkanol from the reaction mixture of step (d) to yield a liquid residue that is substantially free from lower alkanol;
(f) distilling fatty alcohol or alcohols and lower alkyl fatty acid ester or esters of the liquid residue of step (e) to produce (i) an overhead product containing a mixture of a lower alkyl fatty acid ester or esters and fatty alcohol or alcohols and (ii) a relatively involatile residue; and (g) recycling material of the overhead product of step (f) to the hydrogenation step.
(a) subjecting the fatty alcohol fraction to transesterification in the presence of a transesterification catalyst in a first transesterification zone maintained under transesterification conditions, thereby to convert substantially all of any lower alkyl fatty acid ester present in the feed mixture by ester interchange with a corresponding amount of fatty alcohol or alcohols to lower alkanol and to a wax ester derived from a fatty alcohol and a fatty acid;
(b) separating resulting lower alkanol from the reaction mixture of step (a) by vaporisation to yield an intermediate transesterification product mixture that is at least partially free from lower alkanol and contains a fatty alcohol or alcohols and a wax ester or esters;
(c) distilling fatty alcohol or fatty alcohols and wax ester or wax esters of the intermediate transesterification product mixture of step (b) to yield (i) an overhead fraction that contains the fatty alcohol or alcohols and is substantially free from lower alkyl fatty acid ester and (ii) a distillation residue comprising fatty alcohol or alcohols, and wax ester or esters;
(d) subjecting the distillation residue of step (c) to transesterification in the presence of added lower alkanol and of a transesterification catalyst in a second transesterification zone maintained under transesterification conditions, thereby to reconvert wax ester or esters to lower alkyl fatty acid ester or esters and to fatty alcohol or alcohols;
(e) evaporating unreacted lower alkanol from the reaction mixture of step (d) to yield a liquid residue that is substantially free from lower alkanol;
(f) distilling fatty alcohol or alcohols and lower alkyl fatty acid ester or esters of the liquid residue of step (e) to produce (i) an overhead product containing a mixture of a lower alkyl fatty acid ester or esters and fatty alcohol or alcohols and (ii) a relatively involatile residue; and (g) recycling material of the overhead product of step (f) to the hydrogenation step.
3. A process according to claim 1 or claim 2, in which the transesterification catalyst of step (a) is an alkyl titanate.
4. A process according to any one of claims 1 to 3, in which the transesterification catalyst of step (d) is an alkyl titanate.
5. A process according to any one of claims 1 to 4, in which the intermediate transesterification product of step (b) is distilled in step (c) without prior separation of the transesterification catalyst therefrom.
6. A process according to any one of claims 1 to 5, in which the liquid residue of step (e) is distilled in step (f) without prior separation of the transesterification catalyst therefrom.
7. A process according to any one of claims 1 to 6, in which at least a part of the relatively involatile residue of step (f) is recycled to step (c) to provide transesterification catalyst for use in the first transesterification zone.
8. A process according to claim 1 or claim 2, in which the transesterification catalyst of step (a) is an alkali metal alkoxide.
9. A process according to claim 1, claim 2 or claim 8, in which the transesterification catalyst of step (d) is an alkali metal alkoxide.
10. A process according to claim 8 or claim 9, in which the intermediate transesterification product mixture of step (b) is passed through a bed of an acidic ion exchange resin containing -SO3H and/or -COOH groups to neutralise the alkali metal alkoxide prior to the distillation step (c).
11. A process according to any one of claims 8 to 10, in which the liquid residue of step (e) is passed through a bed of an acidic ion exchange resin containing -SO3H and/or -COOH groups to neutralise the alkali metal hydroxide prior to the distillation step (f).
12. A process according to any one of the preceding claims, in which the lower alkyl ester or esters is or are methyl esters and in which the lower alkanol is methanol.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB898900993A GB8900993D0 (en) | 1989-01-17 | 1989-01-17 | Process |
| GB8900993.0 | 1989-01-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2045547A1 true CA2045547A1 (en) | 1990-07-18 |
Family
ID=10650169
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002045547A Abandoned CA2045547A1 (en) | 1989-01-17 | 1990-01-16 | Process |
Country Status (18)
| Country | Link |
|---|---|
| US (1) | US5138106A (en) |
| EP (1) | EP0454720B1 (en) |
| JP (1) | JP2781274B2 (en) |
| KR (1) | KR0167750B1 (en) |
| AT (1) | ATE116633T1 (en) |
| AU (1) | AU637998B2 (en) |
| BR (1) | BR9007039A (en) |
| CA (1) | CA2045547A1 (en) |
| DE (1) | DE69015806T2 (en) |
| ES (1) | ES2069731T3 (en) |
| GB (1) | GB8900993D0 (en) |
| IN (1) | IN175663B (en) |
| MY (1) | MY106264A (en) |
| NZ (1) | NZ232138A (en) |
| OA (1) | OA09381A (en) |
| PH (1) | PH27251A (en) |
| WO (1) | WO1990008123A1 (en) |
| ZA (1) | ZA90331B (en) |
Families Citing this family (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE1006287A3 (en) * | 1992-04-30 | 1994-07-12 | Gheorghiu Mihail | Method for producing fatty acid methyl esters from a natural oil or grease,methyl esters obtained in this way and use of same |
| ZA938109B (en) * | 1992-10-29 | 1994-06-06 | Davy Mckee London | Process for the production of fatty alcohols |
| DE4335781C2 (en) * | 1993-10-20 | 1998-02-19 | Henkel Kgaa | Vegetable-based fatty alcohols and process for their preparation |
| EP0654528A1 (en) * | 1993-11-22 | 1995-05-24 | Mihail Gheorghiu | Process for the production of fatty acid methyl esters from a natural oil or fat, fatty acid methyl esters so obtained, and their use |
| US5532392A (en) * | 1994-01-13 | 1996-07-02 | Gheorghiu; Mihail | Process for the preparation of methyl fatty acid esters starting from natural oil or fat, methyl esters obtained in this way and use thereof |
| US5536889A (en) * | 1995-09-29 | 1996-07-16 | Shell Oil Company | Process for the two-stage hydrogenation of methyl esters |
| DE19939566C1 (en) * | 1999-08-20 | 2001-04-05 | Cognis Deutschland Gmbh | Branched, largely unsaturated ester oils, process for their preparation and their use for the production of cosmetic and / or pharmaceutical preparations |
| US20040047830A1 (en) * | 2002-09-05 | 2004-03-11 | Unilever Home & Personal Care Usa, Division Of Conopco, Inc. | Shaving composition |
| JP4034289B2 (en) * | 2004-04-02 | 2008-01-16 | 花王株式会社 | Method for producing fatty alcohol |
| DE102007033636A1 (en) | 2007-07-19 | 2009-01-22 | Cognis Ip Management Gmbh | Lower alkyl esters separation involves transesterifying of fatty alcohol fraction or fatty alcohol mixture to fatty alcohol, wax esters and lower alkylalcohol |
| US20090119979A1 (en) * | 2007-11-08 | 2009-05-14 | Imperial Petroleum, Inc. | Catalysts for production of biodiesel fuel and glycerol |
| CN102177130A (en) * | 2008-12-04 | 2011-09-07 | 国际壳牌研究有限公司 | Process for preparing alkanediol and dialkyl carbonate |
| WO2010103549A2 (en) * | 2009-03-12 | 2010-09-16 | Godavari Biorefineries Ltd | A method of obtaining policosanols from natural material |
| US9045715B2 (en) * | 2011-05-13 | 2015-06-02 | Cognis Ip Management Gmbh | Process for purifying crude fatty alcohols |
| EP2522650B1 (en) * | 2011-05-13 | 2016-03-09 | Cognis IP Management GmbH | Process for purifying crude fatty alcohols |
| GB201119871D0 (en) * | 2011-11-17 | 2011-12-28 | Davy Process Techn Ltd | Process |
| KR20150046322A (en) * | 2012-08-31 | 2015-04-29 | 롬 앤드 하스 캄파니 | Method to produce alcohols from organic acids |
| GB201218078D0 (en) * | 2012-10-09 | 2012-11-21 | Davy Process Techn Ltd | Process |
| GB201219983D0 (en) | 2012-11-06 | 2012-12-19 | Davy Process Techn Ltd | Apparatus and process |
| DE102013106382A1 (en) * | 2013-06-19 | 2014-12-24 | L'Air Liquide, Société Anonyme pour l'Etude et l'Exploitation des Procédés Georges Claude | Process for the preparation of fatty alcohols from fatty acid methyl ester |
| CN107635660A (en) | 2015-03-26 | 2018-01-26 | 巴斯夫公司 | Hydrogenolysis catalyst with peracid tolerance |
| CN108516924A (en) * | 2018-03-30 | 2018-09-11 | 江苏丰益化工科技有限公司 | A kind of production system for high-purity fatty alcohol |
| CN110860284B (en) * | 2019-11-28 | 2021-04-02 | 浙江大学 | Supported catalyst and preparation method and application thereof |
| WO2024062008A1 (en) * | 2022-09-23 | 2024-03-28 | Firmenich Sa | Transesterification process |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3173959A (en) * | 1965-03-16 | Process for the production of saturated fatty alcohols | ||
| US1491076A (en) * | 1921-04-05 | 1924-04-22 | Us Ind Alcohol Co | Process of alcoholysis |
| GB795573A (en) * | 1955-05-10 | 1958-05-28 | Belge Produits Chimiques Sa | An improved process for the preparation of higher aliphatic alcohols |
| FR1154907A (en) * | 1955-07-05 | 1958-04-18 | California Research Corp | Higher fatty alcohols |
| FR1402133A (en) * | 1964-04-30 | 1965-06-11 | Sinnova Ou Sadic | Process for the preparation of higher fatty alcohols from acid oils or fats of vegetable or animal origin |
| US3949007A (en) * | 1969-08-01 | 1976-04-06 | Bayer Aktiengesellschaft | Process for the production of primary alkenols |
| GB1290094A (en) * | 1970-03-13 | 1972-09-20 | ||
| SU734182A1 (en) * | 1977-07-07 | 1980-05-15 | Ярославский политехнический институт | Method of producing secondary butanol |
| JPS60188334A (en) * | 1984-03-08 | 1985-09-25 | Nisshin Oil Mills Ltd:The | Preparation of higher alcohol |
| ES2064715T3 (en) * | 1989-01-17 | 1995-02-01 | Davy Mckee London | PROCEDURE FOR OBTAINING FATTY ALCOHOLS. |
-
1989
- 1989-01-17 GB GB898900993A patent/GB8900993D0/en active Pending
-
1990
- 1990-01-16 ES ES90901859T patent/ES2069731T3/en not_active Expired - Lifetime
- 1990-01-16 BR BR909007039A patent/BR9007039A/en not_active Application Discontinuation
- 1990-01-16 PH PH39894A patent/PH27251A/en unknown
- 1990-01-16 AU AU49466/90A patent/AU637998B2/en not_active Ceased
- 1990-01-16 KR KR1019900702047A patent/KR0167750B1/en active IP Right Grant
- 1990-01-16 AT AT90901859T patent/ATE116633T1/en not_active IP Right Cessation
- 1990-01-16 WO PCT/GB1990/000065 patent/WO1990008123A1/en active IP Right Grant
- 1990-01-16 DE DE69015806T patent/DE69015806T2/en not_active Expired - Fee Related
- 1990-01-16 US US07/721,437 patent/US5138106A/en not_active Expired - Lifetime
- 1990-01-16 EP EP90901859A patent/EP0454720B1/en not_active Expired - Lifetime
- 1990-01-16 CA CA002045547A patent/CA2045547A1/en not_active Abandoned
- 1990-01-16 JP JP2502361A patent/JP2781274B2/en not_active Expired - Lifetime
- 1990-01-17 MY MYPI90000087A patent/MY106264A/en unknown
- 1990-01-17 IN IN49MA1990 patent/IN175663B/en unknown
- 1990-01-17 NZ NZ232138A patent/NZ232138A/en unknown
- 1990-01-17 ZA ZA90331A patent/ZA90331B/en unknown
-
1991
- 1991-07-15 OA OA60040A patent/OA09381A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| ES2069731T3 (en) | 1995-05-16 |
| OA09381A (en) | 1992-09-15 |
| AU4946690A (en) | 1990-08-13 |
| DE69015806T2 (en) | 1995-05-18 |
| US5138106A (en) | 1992-08-11 |
| PH27251A (en) | 1993-05-04 |
| BR9007039A (en) | 1991-11-12 |
| JP2781274B2 (en) | 1998-07-30 |
| JPH04504411A (en) | 1992-08-06 |
| AU637998B2 (en) | 1993-06-17 |
| NZ232138A (en) | 1992-06-25 |
| KR0167750B1 (en) | 1999-03-20 |
| KR910700221A (en) | 1991-03-14 |
| EP0454720A1 (en) | 1991-11-06 |
| GB8900993D0 (en) | 1989-03-08 |
| EP0454720B1 (en) | 1995-01-04 |
| IN175663B (en) | 1995-08-05 |
| DE69015806D1 (en) | 1995-02-16 |
| MY106264A (en) | 1995-04-29 |
| ZA90331B (en) | 1991-01-30 |
| ATE116633T1 (en) | 1995-01-15 |
| WO1990008123A1 (en) | 1990-07-26 |
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